Quadcutter is one piece ferrule with X-lock 4 blade system ensures blade retention on impact. Individually spin-tested for optimal down-range flight performance. Practice blades included.Features:X-lock blade system ensures blade retention on impact;.031 thick ultra-sharp replaceable razor-sharp stainless-steel blades;Individually spin-tested for optimal down-range flight performance;Practice blades included ultra-sharp replacement blades included: one set;1 3/16" cutting diameter. 100 grain