Check the listing for details. MC4 Socket - For 1/4" Torque Wrench - Assemble MC4 Connectors Correctly!. Condition: New. Listed at 30.00 USD. *UPDATED VERSION* - ONE PIECE DESIGN!Old two piece version is still available here: https://www.ebay.com/itm/326189367965 Finally! A tool to torque the back-nut on MC4 connectors! Every Solar Professional must have an MC4 socket and torque wrench. MC4 connectors are not weatherproof if not assembled properly with the right materials and torqued to the manufacture's specifications! Poorly assembled MC4 connectors can cause all types of issues. Connectors can come apart, melt, cause bad circuit connections, ground faults and insulation faults.... All these issues can be prevented by using the right tools and following the manufactures instructions (NEC 110.3 (B)). Poorly made MC4s can be difficult to find when issues come up. Prevent callbacks by using the right tools the first time! For use with Stäubli MC4 Male and Female Connectors. Use a 1/4" torque wrench set to 30-31 in-lbf (3.4 N m - 3.5 N m) when tightening the back nut of the connector. This torque rating is printed on the side of the socket for your convenience. This MC4 Socket has a 3/8" drive but comes with an adapter to 1/4". Do not use with larger torque wrenches since they will not be as accurate as a 1/4". MC4 connectors must be torqued at time of install. Available in your favorite colors. Special colors available on request. This socket is made in the USA, with USA made ABS Plastic. ABS plastic is light weight, durable and will not crack glass if dropped on an array. This listing does not include a torque wrench, MC4 connectors, or PV Wire. Please purchase separately. Ships in 3-5 days