3M Scotchlok TR-490 is a positive action ratchet tool that crimps both insulated and non-insulated terminals and connectors. It has hardened steel jaws and a corrosion-resistant finish that offers enhanced durability. 3M Scotchlok TR-490 Ratchet Tool effectively crimps nylon, vinyl-insulated or non-insulated, butted or brazed-seam terminals. This tool has a ratchet mechanism which provides positive closure of the handles for a full crimping cycle. It is cushion-gripped, and features a pawl release lever for the removal of misplaced terminals.