Klein Tools Long Arm Hex Key

Twelve sizes, all inch (SAE): 0.050, 1/16, 5/64, 3/32, 7/64, 1/8, 9/64, 5/32, 3/16, 7/32, 1/4 and 3/8 inch. Part numbers run with the size, so LL2 is the 0.050 inch, LL8 the 1/8 inch, LL16 the 1/4 inch and LL24 the 3/8 inch. There are no metric sizes in the line, so if your setscrews are metric this is the wrong series.

On the 3/8 inch LL24 the long arm measures 6-27/32 inches and the short arm 1-15/32 inches. That long leg is what gets you down into a deep counterbore or past an obstruction, with the short leg in your hand as the grip. Use the short end in the fastener when you need leverage in tight quarters instead.

No. The long arm hex key is not insulated and offers no protection against electrical shock. De-energize the circuit before working on it, or use a tool rated and marked for live work. Klein's warning also says not to slip a pipe or other extension over the arm for more leverage.

A long arm L-key is the one to reach with: the extended leg gets into recessed sockets, down between conduit and equipment, and lets you swing the short end as a lever. A short-arm L-key is stiffer and fits where headroom is tight. A T-handle spins faster and gives two-hand torque but cannot reach past an obstruction the way a 6-27/32 inch arm does. For panel and fixture setscrew work where access is the problem, the long arm is the right pick.

LL16 is the 1/4 inch. The neighbouring sizes are LL14 at 7/32 inch and LL24 at 3/8 inch, so the number is not a direct fraction code, and it pays to order by the size you need rather than by eye. For a maintenance kit, ordering LL2 through LL24 covers all twelve inch sizes.

The keys have rust and corrosion resistant surfaces, which is what matters for a tool that lives in a pouch or a truck box through wet weather. They are made in the USA. Still wipe them down after wet use; the finish resists corrosion, it does not make the steel stainless.

Each hex size is its own part number, so you buy the size you need rather than a boxed set. Stocking a service van usually means picking off the small end for device and fixture setscrews (0.050 through 1/8 inch) plus the larger 1/4 and 3/8 inch for equipment and bus hardware.

The LL24 in 3/8 inch is listed at 0.25 pounds. Light enough to carry loose in a pouch, and worth knowing if you are building out a tool kit against a weight allowance.