The MTECH USA MT-1166RB Butterfly Training Blade is a trainer knife with a 4" training blade designed for practicing butterfly knife techniques. The blade edge is dull for safety during training sessions. The handle is made of stainless steel, and the knife is ambidextrous, suitable for both left and right-handed users. This modern folding knife by M-Tech is ideal for collectors or enthusiasts looking to improve their skills without the risk of using a sharp blade.