<p>The QD- Hex Lock System is a unique adjusting mechanism for locking to the proper length of extension to fit your patient needs, adult or pediatric .</p> <p>The Hex over cam design has no threaded parts to gall or cross thread. No "right tight" and so on. Simply align the arrows on cam and shaft for unlocked movable position. Then turn the hex in EITHER direction, until firm and splint length is locked at that point. Simple and effective.</p>