A wire stretcher is a piece of equipment, not used in powerlines, you can send new ground hands to search for. It can be described in any way you see fit. Be sure to be specific when describing what it looks like and where it can be found in the truck (give 1 or 2 fallback locations). If your hand asks what it’s for, you can tell them it’s to stretch the wire out so it can reach a longer distance.
Take note: a wire stretcher is an actual piece of equipment for a different line of work and a different purpose. If you get a ground hand that knows what it is, give up. The bit won’t be funny after that.