The best wire crimping tool available, an absolute must if you make a lot of custom wire sets or wiring. Constructed with a Heavy-Duty hardened steel frame with molded non slip hand grips. An adjustable ratchet mechanism produces consistent factory style high quality crimps. The 300+ Crimp™ Tool is supplied with three removable stripping/crimping die type jaws: one for 7 to 9 Millimeter spark plug wires, one for primary wire terminals, and one for preinsulated terminals.