5/16 Long Arm Alloy Steel Hex Key provides a long arm L-key format for assembly benches, maintenance kits, and equipment service. The ASME B18.3 width band is 0.3110-0.3125 in.; the key is held just under nominal so it enters an in-tolerance socket and bears on the flats.
Instrument and electronics work on the small end of the range depends on compact keys that fit small socket products. Many buyers stock the Long Arm key beside its Short Arm twin so the same width is available in both geometries.
Cold Headers keeps this driver family tied to the broader socket-fastener catalog rather than treating it as a commodity tool. Review the 5/16 in. width, Long Arm format, short-leg length, and arm length before ordering. The listed B and C ranges keep the tool geometry tied to this exact catalog row.
Call 773-775-7900 or email Sales@coldheaders.com for pricing, availability, or a quote.
