Aven's professional grade crimping tool has a smooth and efficient ratcheting mechanism that creates uniform and secure crimps. Variety of dies to extend the versatility of this tool. Ideal for professional electricians and DIY enthusiasts. Tool and dies are made from alloy steel for durability. Die to crimp heat shrink butt connectors AWG 22-18/16-14/12-10/8 (0.5-1.0/1.5-2.5/4.0-6.0/10mm2) included.