Simple and user friendly Limbsaver has eliminated the chance for movement or potential failure resulting in a less cumbersome, and straightforward product. Built for the elements Made from durable Isoplast, the True-Track offers rock-solid performance in all weather conditions. Lightweight and compact Weighs only 7oz. Just throw it in your bag or on your favorite rifle and go! Secure attachment system to remain on target The True-Track comes in two flavors, a traditional sling stud mount and a 1913 Picatinny rail mount. Adjustable and smooth operating Silent adjustments and operation and adjustable from 6"-10". Mfg: Sims Vibration Laboratories