Hilmors T-Handle allen wrench are a upgrade to be HVAC/R friendly. Rugged and Durable Hardened, black-oxide coated shafts increase life and durability. Comfortable Grip Ergonomic molded handles reduce hand fatigue and won't slip or twist. Quick Identification Easy-to-read size markings make identification simple. Added Versatility A 6" shaft works well in tight spaces, while the 5/8" shaft gives you more leverage.