Steve Patrick
08-04-2025
Perfect transaction, sunglasses are awesome and suit me completely. Price was amazing compared to other suppliers.
RB3721CH
£150.00
Was:
RRP:
i
Pay in 4 interest-free payments with
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100% Satisfaction Guarantee
100% Satisfaction Guarantee
We’re committed to ensuring you’re completely satisfied with your purchase. If for any reason you’re not delighted with your glasses, simply let us know, and we’ll make it right. Our 100% Satisfaction Guarantee covers exchanges, adjustments, and even a full refund if needed. Click here to learn more about how we support your satisfaction.
Eligible for 48hr Delivery
Great choice! Your selected product qualifies for our 48-hour Fast Track service. Place your order by 2 pm, Monday through Thursday, with standard single vision, 1.5 index, clear un-coated lenses. If your prescription is within +/- 4.00 sphere (SPH) and +/- 2.00 cylinder (CYL), we’ll have your glasses delivered within 2 business days.
Not Eligible for 48hr Delivery
Please note this product does not qualify for our 48-hour Fast Track service. Only products with in-stock frames and standard single vision, 1.5 index clear uncoated lenses, with a prescription between +/- 4.00 sphere (SPH) and up to +/- 2.00 cylinder (CYL), are eligible for this service. Click here to learn more and see our fast track products!
Eligible for 48hr Delivery
Estimated Delivery:
Eligible for 48hr Shipping
(Subject to Lenses)
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The right size frames
With thousands of frames to choose from, how do you choose a pair of glasses that will fit correctly? On this page, you'll learn two methods for choosing a great-fitting frame, without having to try them on first. These tips are extremely handy if you are considering purchasing your next pair of glasses on the internet. If you do decide to buy online, it is advisable to choose a supplier that offers an exchange or return service, just in case!
Calculate Your Frame Width
Determining your frame width is crucial for selecting glasses that fit well and look great. It's a simple step that guides you to the ideal eyewear size for optimal comfort and style. Follow these steps for a perfect fit:
Measure the width of one lens to find your eye size. Multiply your eye size by 2.
Measure the width of the bridge (the part over your nose).
Add 11mm to account for the frame's arm width from the front.
Example: If your eye size is 50mm and your bridge width is 20mm:
Double Eye Size: 50mm x 2 = 100mm
Add Bridge Width: 100mm + 20mm = 120mm
Add for Arms: 120mm + 11mm = 131mm
Your ideal frame width is 131mm(+ or - 4mm for flexibility).
Our Helpful Sizing Tool
| Size | Measurement (mm) |
|---|---|
| Small | 115-135 |
| Medium | 130-140 |
| Large | 135-145 |
| Extra Large | 140-155 |
Our sizing tool simplifies the process of finding the perfect glasses by categorising them into four sections: Small, Medium, Large, and Extra Large. With just a few clicks, you can find the size that will provide the best fit and comfort. Our tool helps us deliver glasses that fit well and look great, and it's available under the "size" dropdown on our catalogue pages. If you're looking for something more specific, you can adjust the sizing sliders under the "Advanced sizing" option. Find your perfect pair with ease using our sizing tool.
Finding your frame size
When selecting a new pair of glasses, it's important to know your frame size to ensure a comfortable and proper fit. This diagram illustrates where to find the size measurements on your current pair of glasses. Typically, these measurements are located on the inside of the arm and are listed in millimeters. The first number represents the lens width (Eye size), the horizontal diameter of one lens6. The second number is the bridge width, the distance between the two lenses. Lastly, the third number indicates the length of the arm. To find the best fit, compare these measurements to the size specifications of the new glasses you are considering.
The number on the left-hand side of the square box is the "Eye Size" and is sometimes referred to as the "A" measurement. This is the width of the lens at its widest point measured in millimetres (see A in the diagram below).
The number on the right-hand side of the square box is the "Bridge Width" and is sometimes referred to as the "DBL" (distance between lenses). This is the distance between the two lenses measured in millimetres.
You may also find a third, three-digit number. This is the "Arm Length". The arm length is measured in millimetres from the attachment screw to the tip of the arm. The measurement is made before the bend is put into the arm.
Lens Depth
You may have noticed that thus far, we have not mentioned the Lens Depth. This measurement will largely depend on the style of frame you decide upon and in many cases, is not required to identify a good-fitting frame. However, if you are choosing glasses for bifocals or varifocals, be mindful that the shallower the frame is, the less area there will be available for the reading element of your lens.
When purchasing Varifocals we recommend a Lens Depth of at least 27 millimetres. For this reason, at Spex4Less, Varifocal lenses will not be available to purchase on frames with a lens depth of fewer than 27 millimetres.
Close
The right size frames
With thousands of frames to choose from, how do you choose a pair of glasses that will fit correctly? On this page, you'll learn two methods for choosing a great-fitting frame, without having to try them on first. These tips are extremely handy if you are considering purchasing your next pair of glasses on the internet. If you do decide to buy online, it is advisable to choose a supplier that offers an exchange or return service, just in case!
Calculate Your Frame Width
Determining your frame width is crucial for selecting glasses that fit well and look great. It's a simple step that guides you to the ideal eyewear size for optimal comfort and style. Follow these steps for a perfect fit:
Measure the width of one lens to find your eye size. Multiply your eye size by 2.
Measure the width of the bridge (the part over your nose).
Add 11mm to account for the frame's arm width from the front.
Example: If your eye size is 50mm and your bridge width is 20mm:
Double Eye Size: 50mm x 2 = 100mm
Add Bridge Width: 100mm + 20mm = 120mm
Add for Arms: 120mm + 11mm = 131mm
Your ideal frame width is 131mm(+ or - 4mm for flexibility).
Our Helpful Sizing Tool
| Size | Measurement (mm) |
|---|---|
| Small | 115-135 |
| Medium | 130-140 |
| Large | 135-145 |
| Extra Large | 140-155 |
Our sizing tool simplifies the process of finding the perfect glasses by categorising them into four sections: Small, Medium, Large, and Extra Large. With just a few clicks, you can find the size that will provide the best fit and comfort. Our tool helps us deliver glasses that fit well and look great, and it's available under the "size" dropdown on our catalogue pages. If you're looking for something more specific, you can adjust the sizing sliders under the "Advanced sizing" option. Find your perfect pair with ease using our sizing tool.
Finding your frame size
When selecting a new pair of glasses, it's important to know your frame size to ensure a comfortable and proper fit. This diagram illustrates where to find the size measurements on your current pair of glasses. Typically, these measurements are located on the inside of the arm and are listed in millimeters. The first number represents the lens width (Eye size), the horizontal diameter of one lens6. The second number is the bridge width, the distance between the two lenses. Lastly, the third number indicates the length of the arm. To find the best fit, compare these measurements to the size specifications of the new glasses you are considering.
The number on the left-hand side of the square box is the "Eye Size" and is sometimes referred to as the "A" measurement. This is the width of the lens at its widest point measured in millimetres (see A in the diagram below).
The number on the right-hand side of the square box is the "Bridge Width" and is sometimes referred to as the "DBL" (distance between lenses). This is the distance between the two lenses measured in millimetres.
You may also find a third, three-digit number. This is the "Arm Length". The arm length is measured in millimetres from the attachment screw to the tip of the arm. The measurement is made before the bend is put into the arm.
Lens Depth
You may have noticed that thus far, we have not mentioned the Lens Depth. This measurement will largely depend on the style of frame you decide upon and in many cases, is not required to identify a good-fitting frame. However, if you are choosing glasses for bifocals or varifocals, be mindful that the shallower the frame is, the less area there will be available for the reading element of your lens.
When purchasing Varifocals we recommend a Lens Depth of at least 27 millimetres. For this reason, at Spex4Less, Varifocal lenses will not be available to purchase on frames with a lens depth of fewer than 27 millimetres.
Close
Frame Details:
- Hinge Type: Sprung Sides
-
Size:
XFind your frame size
Use our glasses size calculator to find your ideal size. Enter your frame measurements below (usually found inside the temple arm or nose bridge).
Lens must be between 40 and 70
Bridge must be between 10 and 20
Your Recommended Size is
- Material: Metal
- Delivery: (Sourced from Italy)
- Price:
-
- Gender: Unisex
-
Multifocal:
Available
Multifocal
This frame is compatible with multifocal lenses, including varifocal, bifocal, and occupational lenses. Multifocal lenses are ideal if you need vision correction at multiple distances, such as for reading, computer work, and seeing far away—all in one pair of glasses.
Choosing multifocal lenses means you can enjoy clear, seamless vision without the need to switch between different pairs of glasses.
Need help deciding? Our opticians can guide you on the best lens option for your lifestyle.
- Frame Type: Full Rimmed
- RRP:
- Nose Pad: Regular
- Frame Shape: Square
- Brand: Ray-Ban
- Colour:
- SKU:
140 mm
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Description
Elevate your style with the RB 3721CH Ray-Ban Sunglasses, crafted meticulously with a robust metal frame that promises both durability and a sleek, sophisticated look. The deep frame design exudes a modern flair, perfectly complementing any face shape while ensuring a comfortable, secure fit. Designed by Ray-Ban, a brand synonymous with timeless elegance and superior craftsmanship, these sunglasses are ideal for every occasion, from casual strolls to upscale events. The minimalist yet striking design features distinct, clean lines that highlight the premium quality of the metal finish. The adjustable nose pads add an extra layer of comfort, allowing for a customised fit that stays in place effortlessly. Whether you're dressing up for an important meeting or dressing down for a laid-back weekend, the RB 3721CH pairs seamlessly with any outfit, making you look effortlessly stylish and assured. Choosing these frames means investing in a piece of eyewear that’s not just functional but a bold fashion statement. Enjoy the confidence that comes with wearing Ray-Ban, knowing you're adorned with one of the most iconic brands in eyewear history. Embrace a blend of style, comfort, and versatility with these impeccable Ray-Ban sunglasses.
Delivery & Returns
| Non-Prescription Lenses | Standard Lenses | Specialist Lenses |
|---|---|---|
If you're not satisfied with your purchase from Spex4Less, you can request a return or exchange within 7 days for prescription glasses or 14 days for non-prescription items. Items must be returned in their original condition. For more details, visit the Exchanges & Returns page.
Explore Our Range of Lens Options
Designed With You In Mind
All our lenses are custom-fit to your needs. This includes the largest range of customisation options.
See Your Lens Options
Lenses for Every Situation
Glasses that match how you live—whether you're behind the wheel, at a desk, or on the go.
Find Lenses for Your Life
Custom Tints and Lens Coatings
Enhance your lenses with a variety of tints and coatings, from anti-glare to blue light protection.
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