Free Shipping
Price Match
Easy Returns
Licensed Opticians
The Ray-Ban 3721 sunglasses combine modern square styling with advanced LiteForce technology for a lightweight, durable everyday frame. Part of Ray-Ban's innovative LiteForce collection, these unisex sunglasses feature a full-rim metal construction that balances the clean lines of a contemporary square shape with the comfort features you need for all-day wear.
LiteForce Technology: Lightweight Meets Durability
The RB3721 incorporates LiteForce material—a premium thermoplastic originally developed for aerospace and medical applications. This advanced material delivers exceptional strength and chemical resistance while keeping the frame remarkably light on your face. The metal front pairs with rubber temple tips that provide a secure, non-slip grip, so your sunglasses stay put whether you're driving, walking, or just going about your day.
Adjustable nose pads let you fine-tune the fit to match your face shape and bridge height. This customization prevents slipping, reduces pressure points, and ensures the optical center of the lens aligns properly with your pupils—critical for both comfort and clear vision, especially if you add prescription lenses.
Prescription-Ready Square Frames
These sunglasses are fully compatible with prescription lenses, including single-vision, bifocal, and progressive options. The 59mm lens width and full-rim design provide ample coverage and work well with a range of prescriptions. The square shape flatters round and oval face shapes by adding definition and structure.
All Ray-Ban lenses deliver 100% UVA and UVB protection. The RB3721 is available in four color combinations: Brown on Gunmetal with brown gradient lenses, Black on Silver with dark green lenses, Black on Gold with grey gradient lenses, and Black on Black with dark grey lenses. Each features the signature Ray-Ban logo etched on the lens and embossed on the temples.
Frame measurements are 59-17-145mm (lens width-bridge-temple length), offering a large fit that works for a variety of face sizes. The single bridge design and adjustable pads make this a practical choice for anyone seeking a modern metal frame with the performance edge of LiteForce construction.
Product Details
Product DetailsModel
0RB3721Shape
Gender
Material
Bridge Type
Rim Type
Age Group
Color Details
Color DetailsFrame Color
BrownColor Code
188/13Color Description
Brown On GunmetalLens Color
Brown
Frame Color
BlackColor Code
914471Color Description
Black On SilverLens Color
Dark Green
Frame Color
BlackColor Code
187/11Color Description
Black On GoldLens Color
Grey
Frame Color
BlackColor Code
186/87Color Description
Black On BlackLens Color
Dark Grey
Frame Color
BlackColor Code
002/B1Color Description
BlackLens Color
Dark Grey PolarizedLens Features
polarized
Size Details
Size DetailsBridge Width
17.00Temple Length
145.00Size
5917-145
Bridge Width
17.00Temple Length
145.00Size
5917-145
Bridge Width
17.00Temple Length
145.00Size
5917-145
Bridge Width
17.00Temple Length
145.00Size
5917-145
Bridge Width
17.00Temple Length
145.00Size
5917-145
Very good quality sunglasses
I was unfamiliar with Designer Optics, but am glad I took the leap of faith and ordered from them. The Ray Bans I purchased are legit, and they were shipped promptly and without any issues.
California Proposition 65 Proposition 65 is a California regulation that requires special warnings to be presented to customers if a product contains certain quantities of chemicals or toxicants known to the State of California to cause cancer, birth defects, or other reproductive harm. The following warning applies to the products linking to this page:
WARNING: Reproductive Harm – https://www.p65warnings.ca.gov/Free Shipping within the contiguous US only (excluding Hawaii and Alaska) on all Orders over $100.
At DesignerOptics.com we are committed to the highest quality of service.
We ship products to all 50 US states as well as to many other countries around the world. We take all the measures to ship our items in a timely manner, directly to your door, almost anywhere in the world.
In stock products usually ship within two business days, but may take up to five business days*. When an order ships you will receive a confirmation email with the tracking information. You can also track your order by logging into your account.
We provide FREE SHIPPING on all orders over $100 We also offer overnight and second day delivery shipping options. Please note that when using next day or second day delivery it still takes 48 to 72 Business hours for the order to be processed.
The Designer Optics Low Price Guarantee is simple:
Designeroptics.com matches the price of all retail competitors and major online retailers.
How it works:
Place the frames in your cart
Before placing your order in add the following the comments box, Add the URL (web address) of the page where you found the lower-priced item,
Your credit card will not be charged until we have confirmed with you by phone or by email that your item qualifies for our Price-Match Guarantee.
Please Follow those easy steps for returns
1- Please fill out this form Return Authorization Form to get an RMA # you will receive a RMA # with instruction on how to return them within 48 to 72 Business hours from the time you submitted the form. Wait for our confirmation e-mail before shipping back the return
2- Send the product back to us following the instructions indicated in our e-mail and to the address we will provide you.
3- Make sure to confirm with us via e-mail the shipping date, the shipping service you used and the tracking number whenever you have
4- Include details of the return and how you would like for us to go about it (refund, store credit, exchange, etc). Designer Optics is not responsible for items damaged along the way.
Please allow us 3 to 5 business days from when items are received for us to process the refund. The amount to be refunded will not include shipping charges. if the order consists of 3 or more frames we will charge a 20% Restocking fee. otherwise only the shipping will be deducted.
Some exclusions may apply. Please note prescription lenses are final sale. We also do not accept returns on beauty products due to health and safety concerns. For more information please go to Returns
At Designer Optics, our skilled and experienced lab opticians play a crucial role in ensuring the quality and accuracy of your eyewear. With over 30 combined years of experience and full licensure, they review each prescription carefully and are equipped to answer any questions you may have.
Our state-of-the-art lab is equipped with the latest technology and equipment, including advanced edging and cutting technology, to produce lenses that are precise and accurate. Whether you need full frame or rimless lenses, our team is dedicated to providing the best possible results.
For personalized support, simply send an email to Support@designeroptics.com to request a call back from one of our friendly opticians.
Frequently Asked Questions
Are the Ray-Ban 3721 sunglasses prescription-ready?
Yes, the Ray-Ban 3721 frames are fully prescription-ready and compatible with single-vision, bifocal, and progressive lenses. The full-rim metal construction and 59mm lens width accommodate a wide range of prescriptions. The adjustable nose pads help ensure proper optical alignment for clear vision.
What is LiteForce technology in Ray-Ban sunglasses?
LiteForce is a premium thermoplastic material used in aerospace and medical industries that Ray-Ban incorporates into select frames. It provides exceptional strength, durability, and chemical resistance while remaining extremely lightweight—as light as plastic but with the reduced thickness and strength of metal. This makes the RB3721 comfortable for extended wear.
What size are the Ray-Ban 3721 sunglasses?
The Ray-Ban 3721 measures 59-17-145mm, which translates to a 59mm lens width, 17mm bridge width, and 145mm temple length. This is considered a large fit that works well for medium to larger face sizes. The lens height is approximately 44.5mm, providing good coverage.
Do the Ray-Ban 3721 sunglasses have adjustable nose pads?
Yes, the RB3721 features adjustable nose pads that can be customized for a personalized fit. These pads help prevent slipping, reduce pressure on the bridge of your nose, and ensure proper lens alignment. They're especially helpful for people with low nose bridges or those who need a more secure fit.
What face shapes work best with the Ray-Ban 3721?
The rectangular square shape of the RB3721 is flattering on a variety of face shapes, particularly round and oval faces. The sharp angles and clean lines of the square frame add structure and definition to softer facial features, creating a balanced, contemporary look.
Do Ray-Ban 3721 sunglasses provide UV protection?
Yes, all Ray-Ban 3721 sunglasses provide 100% UVA and UVB protection, blocking harmful ultraviolet rays to protect your eyes. This UV protection is built into the lenses regardless of tint color, making them safe for everyday sun exposure and outdoor activities.
Compare With Similar Frames
How the Ray-Ban 3721 Sunglasses stacks up against the closest alternatives we carry.
- Iconic retro square design with vintage appeal
- Acetate construction is durable and doesn't require nose pad adjustments
- Typically lighter price point
Read the full comparison
Ray-Ban 3721 vs. Ray-Ban Square 1971: Metal LiteForce or Classic Acetate?
Both the Ray-Ban 3721 and the Square 1971 deliver the modern square aesthetic Ray-Ban is known for, but they take different approaches to construction and fit. If you're deciding between these two, here's what sets them apart.
The RB3721 is built with LiteForce technology—a premium thermoplastic material combined with a metal front that's engineered for lightweight durability. It features adjustable nose pads that let you customize the fit to your face, plus rubber temple tips that grip securely during activity. This makes the 3721 ideal if you need a frame that stays put, especially if you're adding prescription lenses or have a lower nose bridge. The metal construction gives it a sleek, contemporary edge.
The Square 1971, on the other hand, is a classic acetate frame with a retro-inspired look that's been popular since the 1970s. It has a bold, substantial frame presence and rests directly on your nose without adjustable pads—simpler and lower-maintenance, but less customizable. The 1971 is perfect if you prefer the vintage vibe and don't need fit adjustments.
Which should you choose? Go with the RB3721 if you want modern LiteForce technology, adjustable fit features, and a secure grip for active wear or prescription use. Choose the Square 1971 if you're drawn to the iconic retro aesthetic and prefer a straightforward acetate frame without extra hardware. Both are prescription-ready and offer full UV protection—it comes down to whether you prioritize adjustability and tech (3721) or classic style and simplicity (1971).
At a Glance
Ray-Ban Square 1971 Sunglasses
Pros:
- Iconic retro square design with vintage appeal
- Acetate construction is durable and doesn't require nose pad adjustments
- Typically lighter price point
- Bold frame presence for a statement look
Cons:
- Lacks adjustable nose pads for customized fit
- Plastic frame may feel heavier than LiteForce metal
- No rubber temple grips for secure hold
- Less modern tech compared to LiteForce construction