Klein Tools 7/16-Inch Nut Driver

Yes, the shaft is hollow, so it slides down over long bolts and studs instead of bottoming out on them. That is what makes it work on stacked circuit boards and similar long-threaded assemblies. Two shaft lengths are offered: a 3-inch hollow shaft (S14) and a 6-inch hollow shaft (S146). Pick the 6-inch if the stud projects more than a couple of inches past the nut.

No. The S14 is not insulated and will not protect against electrical shock. De-energize the circuit before using it. If you need to work on or near energized conductors, you need a driver built and marked as insulated, not this one. Eye protection should be worn either way.

For most sheet metal screws, enclosure nuts and strut hardware the 3-inch shaft (S14) is the standard working length and is easier to control in tight gear. Step up to the 6-inch (S146) when you need reach past an obstruction or the stud is long enough that a 3-inch hollow shaft would bottom out on it. Both are the same 7/16-inch SAE tip.

No, the S14 is not magnetic. The hollow shaft keeps the nut captured while you are threading it on a stud, but a loose nut will not stick to the tip. On overhead or deep-enclosure work where a dropped nut is a problem, choose a magnetic-tip driver or use a nut starter.

Internal flanges anchor the steel shaft inside the handle to resist twisting, so the shaft is not just press-fit. The shaft is also chrome plated, which helps against corrosion in damp mechanical rooms and service trucks. The driver meets or exceeds applicable ASME/ANSI specifications and is made in the USA.

Klein color-codes the Comfordome handles by size, and the 7/16-inch has a brown handle. The grip is plastic with a smooth dome shape meant to sit in the palm, so it reads by color rather than by squinting at the stamp.

About 0.2 lbs, which is light enough that it adds nothing noticeable to a service pouch. Handle footprint is 1 inch by 1 inch, so it sits in a standard tool roll loop alongside the other Comfordome drivers.