With millions of errant storm trooper laser blasts bouncing around, someone has to repair all of the damage. That's where the WED Treadwell droid comes in. They fix, finesse and basically keep the "Star Wars" protagonists out following their quests instead of dawdling in the space version of a tire shop.
Treadwells vary by era and location but they're similar in that they all have a familiar wide, flat base on top of tank-like treads and pole neck, on which binocular optical sensors are mounted. They're also equipped with a series of spider-like arms (though some have more arms than others) that terminate in various tools for the multitude of projects they face.
Perhaps most notably, a Treadwell (specifically a WED-15-77 model) assisted Luke Skywalker with his family's moisture farming operating on Tatooine. During one deleted scene, the Treadwell malfunctioned just as Luke was planning to meet a friend. So Luke abandoned the droid, which was subsequently nabbed by desert scavengers. So much for taking care of your droid friends, huh, Luke?