Klein Tools SS12 3/8-Inch Stubby Nut Driver 1-1/2-Inch Hollow Shaft

No. The SS12 is not insulated and will not protect against electrical shock. Use it on de-energized equipment only, and wear approved eye protection. If you need to work energized, you need a VDE-rated insulated driver instead, not this one.

One size only: 3/8 inch. It drives 3/8-inch hex nuts and 3/8-inch hex-head sheet metal screws and slotted hex-head screws common in panel and enclosure work. There is no other size on this tool, so for a set of sizes you need the multi-size stubby nut driver set.

No. The Klein Tools SS12 3/8-inch stubby nut driver is non-magnetic, and its shaft is hollow so it can pass over long bolts and stacked circuit board standoffs instead of capturing a nut on the tip. If you need the fastener held for you, the Milwaukee 49-66-4533 SHOCKWAVE Power Groove is a magnetic nut driver, in 5/16 inch by 2-9/16 inch. Note the size change: that is a 5/16 inch socket, not 3/8 inch.

They are different tools for different jobs. The Klein SS12 is a hand-driven stubby nut driver with a 3/8-inch hollow shaft, a 1-1/2 inch shaft length and a 3.75 inch overall length, built around a Comfordome handle you turn by hand. The Milwaukee 49-66-4533 is a SHOCKWAVE Power Groove Impact Duty 5/16 inch by 2-9/16 inch magnetic nut driver bit, meant to be chucked into a drill or impact driver rather than turned by hand. If you are seating 3/8-inch nuts by hand in a tight panel, the SS12 is the hand tool; if you are running 5/16-inch fasteners off a driver, the Milwaukee bit is the one.

Overall length is 3.75 inches with a 1-inch handle height and width, which is why it is called a stubby. It fits where a standard nut driver has no swing room, like inside a loaded panel, behind equipment, or in a shallow box. Weight is 2.4 oz, so it sits fine in a shirt pocket or pouch.

It is a hand tool with a molded Comfordome handle, not a power bit. There is no hex shank to chuck into a drill or impact driver. For powered work you want an impact-rated bit holder style driver like the Milwaukee SHOCKWAVE Power Groove impact duty nut driver; the SS12 is for controlled hand torque in tight spots.

Only if the opening allows a powered driver. The Klein SS12 is a stubby design at 3.75 inches overall with a 1-1/2 inch shaft, specifically so it can be turned by hand where there is no room to swing a full-length driver. The Milwaukee 49-66-4533 is a 2-9/16 inch impact-duty bit that still needs the length of a drill or impact driver behind it, so total clearance required is considerably greater. The Milwaukee is also 5/16 inch where the Klein is 3/8 inch, so they do not cover the same fastener.

Neither is an insulated tool. The Klein Tools SS12 is explicitly not insulated and will not protect against electrical shock, and the Milwaukee 49-66-4533 SHOCKWAVE is an impact-duty driver bit rather than an insulated hand tool. For energized work you need a tool rated and marked for it; both of these are for de-energized assembly and fastening.

By handle color. The 3/8-inch SS12 has a blue handle, part of Klein's color-coded Comfordome handle system, so you can grab the right size out of a pouch without reading the stamp.

The handle uses internal flanges that anchor the shaft against twisting, and the shaft is chrome-plated to resist corrosion. Klein states the tool meets or exceeds applicable ASME/ANSI specifications. It is made in the USA.