These are used to crimp terminals onto wires for the 12V electrical system. The top tool with the yellow handles is the cheap version we bought first. It can be used to cut wire, strip insulation, and crimp terminals – but it does a bad job of all these tasks. So after struggling with this tool, I splashed out and got a proper ratcheted crimping tool, which makes a reliable crimp, without damaging the terminal insulation. “Buy cheap, buy twice”, as they say…

£29 from 12 Volt Planet