What AWG range should I look for?

For general electrical and automotive work, 22-10 AWG covers most insulated spade, ring, and butt connectors. Ferrule work for control panels often needs to extend down to 26-28 AWG and up to 5-7 AWG for larger conductors. Match the printed AWG range on the tool to the wire gauges you actually use rather than buying the widest spec available.