SIEMON CPT CABLE PREPARATION TOOL NEW The CPT provides a simple and effective method to remove the outer cable jacket from 2-, 3, or 4 pair cables without damaging the inner conductor insulation. by inserting the cable into the tool's slot 38.1mm (1.5"), and rotating the tool one full rotation, the outer jacket can be easily pulled off. The CPT is recommended for use with any round cable with an exterior diameter from 2.54 - 6.35mm (0.100" - .0250") and an outer jacket thickness from 0.380 - 0.635 mm (0.015" - 0.025").