Tac-Force 8.5" Iridescent Butterfly Style Spring Assisted Opening Pocket Knife - Tophatter's Inc. Weapons Store OnlineButterfly knives have been around for ages but since their legality is somewhat of a question in some states throughout the US, this is the next best thing. This beautifully designed spring assisted opening pocket knife is deadly to behold and can scare away sny people looking to do you harm. The 3. 75 stainless steel blade is razor sharp, corrosion resistant and easy to maintain. All this comes at a very reasonable price. TAC FORCE Spring assisted