For "ring" cutting the sheating of inside type plastic, fabric or rubber covered cable. Cut through sheathing limited to .031" (.787mm) or .018" (.457mm). This tool is most practically suited for the customary inside type 3/16'' (4.7mm), 1/4" (6.4mm), 3/8" (9.5mm) or 1/2" (12.7mm) cables, but will handle thin sheathed cable up to 1" (2.5cm) in diameter. Cable is pushed into tool and against the spring. Back pressure holds the cable against the cutting blade. And accurate 0.31" (.787 mm)  deep cut is made when the tool is rotated around the circumfrence of the cable.