The Aven Tools 10179 Crimping Tool is a high-precision wire ferrule crimper with a built-in ratchet that applies correct pressure to ensure a complete crimp every time. The crimper features a safety release function that allows you to stop a faulty crimp before the crimping cycle is complete. The precisely milled, hardened steel dies have individual square crimping slots for each wire size from 10 to 6 AWG. The dies can be easily changed using a slotted screwdriver. The durable ABS grips make the crimper comfortable and easy to use.