Single caliper head design is a SCOTT exclusive and it offers some key advantages. First, a single caliper release is simple there are fewer moving parts. Also, the flat side of the head tends to guide the string loop. A single caliper head is also more compact, and it gives you crisp activation and allows for generally lighter trigger settings. The Mongoose XT is the best trigger release SCOTT has ever made! It's a single caliper design which is a SCOTT exclusive and gives you crisp trigger activation and reliable performance. The Mongoose XT also offers a ShutDown self-closing spring-loaded jaw, a SCOTT first. This feature ensures foolproof string loop engagement so youll always be in shooting mode.