| XS | S | M | L | XL | XXL | |
|---|---|---|---|---|---|---|
| Men | 118-123 | 124-129 | 130-135 | 136-141 | 142-147 | 148+ |
| Women | 114-119 | 120-125 | 126-131 | 132-137 | 138-143 | 144+ |
| Kids | 107-112 (Infant) | 113-118 (Toddler) | 119-124 (Little Kids) | 125-130 (Big Kids) | - | - |
Ray-Ban RB3721 LiteForce
That Was a Popular Color.
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We currently don't have any in stock, but we can get you some.
Free Shipping
Don't pay a cent for standard shipping ever again. Other shipping options are available. Learn More
Not 100% satisfied with your purchase? Return them within 45 days for a full refund or exchange. Learn More
FSA/HSA Accepted
Flexible spending accounts (FSA), health savings accounts (HSA), and out-of-network vision insurance coverage can all be used towards awesome new prescription sunglasses, eyeglasses, and goggles. Learn More
See Better Guarantee
We know you work hard for your money, which means you’re looking for the best value you can find. At SportRx, we go beyond premium brand names and prescription lenses. We give you friendly professionals to help you find what you need and 45 days to make sure you’re happy with your purchase. Your satisfaction is our promise, or your money back. Learn More
Part of the LiteForce collection, Ray-Ban RB3721 is the perfect pair of sunglasses for those who demand quality and enjoy style. RB3721 LiteForce is a great all-around everyday sunglass. LiteForce technology guarantees a lightweight and durable frame. Rubber temple tips offer the grip of a performance frame, and adjustable nose pads provide the stability and comfort of a lifestyle frame. The metal frame front and silver logo temple accents provide the recognizable Ray-Ban style you know and love. Flattering on a variety of face shapes, the rectangular Ray-Ban RB3721 LiteForce is available in a large fit. Customize your sunglasses with authentic Ray-Ban prescription lenses, or SportRx Sport Optimized lenses.
Product Overview
Product details
Frame Materials
Metal
Safe from Harmful UV Rays
Block carcinogenic ultraviolet (UV) light from reaching your eyes. With 100% UV protection, your eyes are safe from absorbing harmful sun rays.
6 Base
The most common base curve for casual wear glasses. These types of glasses will have a slight curve to the lenses and frame, but are still fairly flat.
Included Accessories
Cleaning Cloth, Soft Case
SportRx Frame Width™
138mm
138mm
SportRx Frame Width™ (SFW) is the measurement our Sports Opticians use to find the most accurate fit possible. Unlike most eyewear measurements that have little to do with fit, SFW serves as an indicator for how well a frame or goggle will fit your face.
NEED HELP WITH FIT OR PRESCRIPTION?
Talk with one of our friendly Sports Opticians.
SportRx Frame Width™ Chart
*All Sizes in Millimeters
DETERMINING YOUR SFW
Use Eyeglasses and Not Sunglasses
Using flatter eyeglasses makes for a more accurate measurement. It takes a bit more finesse with wrapped sunglasses to get an accurate SFW measurement.
Have more than one pair?It never hurts to have more than one 'frame' of reference! If you have more than one pair that you love, you can measure multiple pairs and get an average.
Make sure the glasses fit!
Since we're using your glasses as a template for ideal fit, make sure they're a pair that are comfortable: not too wide, not too narrow. A quick glance in the mirror will show if the frames spread too far past the edges of your face or seem to 'pinch' it.
How/What do I measure?Measure with the temples opened out fully. Aim for right behind the hinge and measure from the inside of the frame material of one side to the inside of the other side.
FINDING YOUR BRIDGE FIT
Finding the right eyewear for your face means two things: the right frame size and the right bridge style. At SportRx, we have three different bridge styles:
Standard
A standard nose bridge is best for those with nose bridges that go higher than their pupils, or if you have more narrow cheekbones. Standard nose bridges are fixed and don’t include adjustable nose pads.
AdjustableAn adjustable nose bridge includes flexible nose pads that can be adjusted for a firm, yet comfortable hold. This style is best for those who prefer a more customizable fit.
Low-Bridge
The low-bridge fit is designed for those with narrow nose bridges or cheekbones higher than their nose bridge. Also called Asian Fit, this is a great choice if your frames tend to slide down or touch your cheeks.
Size & Fit Guide
FRAME WIDTH
138mm
Frame Width is the measurement our Sports Opticians use to find the most accurate fit possible. Unlike most eyewear measurements that have little to do with fit, SFW serves as an indicator for how well a frame or goggle will fit your face.
Bridge Width
17mm
Finding the right eyewear for your face means two things: the right frame size and the right bridge style. At SportRx, we have three different bridge styles: Standard, Adjustable, Low-Bridge.
Lens Width
59mm
Lens Height
45mm
Temple Length
145mm
