A cable ripper is a simple tool with one function: removing the outer jacket on ROMEX and other electrical wires. One of Ideal’s versions, the Lil’ Ripper Stripper, incorporates some other commonly-used tools to let you rip, clip, strip, loop, and twist with one tool.
Besides ripping the outer jacket of ROMEX, the tool also clips it. It also can be used to strip insulation from wires, form loops in wires for screw terminals, and get a better grip on wire nuts with wings. The grip is injection molded elastomer and a measurement scale is molded into the side for measuring the correct amount of wire to strip.
You can pick up Ideal’s Lil Ripper Stripper for about $6.