Snap-on extension connectors Snap-on Tools' extension connectors add versatility to extensions, breaker bars, ratchets and crowfoots when accessing fasteners in hard to reach areas, saving time and aggravation. The connectors act like an erector set, allowing tech to connect one, two or more tools together to make different shapes, lengths and angles. Common applications include transmission bell housing bolts, engine mounts used behind semi-truck dash boards, radiator fans, belt tensioners and crankshaft bolts. Snap-on offers connectors in two sizes: the 3/8" female and male 90 degree extension connector (FZ1) and the 1/4" female and male 90 degree connector (TZ1).