With the VDT (Velocity Drop-AwayTechnology) this rest boasts Smart-RestTechnology. The patented VDT knowsto only drop away when the bow is fired.The ULTRA-REST is the only arrow reston the market to offer these features.LDT (LOCK-DOWN TECHNOLOGY)eliminates rest bounceback--guaranteeingtotal fletching clearance. Increased speedand accuracy offers minimal friction andzero fletching contact. Also shoots theshortest arrows possible. Up to 4 shorterthan the competition. MADE IN AMERICA