The Flexmeter Double Sided Wrist Guards has a specific purpose in the design: Flexmeter assures wrist protection, while allowing full mobility of your wrists. The Single Sided Flexmeter has a single dorsal support that sits on top of your arm and wrist. The support is strap securely with three individual straps. Ideal for snowboarding, inline skate and roller derby. The Flexmeter wrist guard has been designed by physicians, engineers and trauma specialists. The Flexmeter wrist guard is a dorsal protection worn on the back of the wrist which disperses initial impact loads up the forearm by transferring the energy. You can kind of compare it to a shock on a car. When you hit a bump the force is absorbed by the shocks. The Flexmeter wrist guard is designed the same way. As your wrist is impacted the plastic shields and straps act like a shock to absorb the impact and energy. With the Flexmeter wrist guard, the hands and fingers are prevented from being outstretched and are therefore not subject to a reverse extension injury.