This is the Klein 631 — a 7-piece set of hollow-shaft nut drivers in sizes 3/16, 1/4, 5/16, 11/32, 3/8, 7/16, and 1/2 inch, each with a 3-inch full hollow shaft. The hollow shaft is what matters: a long bolt or threaded rod runs up inside the driver rather than stopping at the socket, which means the driver works on bolts that are longer than the shaft itself.
It’s the set that lives in an electrician’s bag for panel work, device installs, and any job where threaded rod hangers or long bolts would stop a standard nut driver cold. The cushion-grip handles give consistent torque without slipping, and each driver is color-coded by size for fast selection in a gang box or panel.
Klein Tools has been making hand tools for electricians and tradespeople since 1857, headquartered in Lincolnshire, Illinois. The Journeyman and Standard pliers lines — along with many of Klein’s cushion-grip screwdrivers — are forged and finished in the United States, and clearly marked as such, so you know exactly what you’re buying.
