Abstract: A closed end box line wrench includes at least one wrench end and a tool body. The wrench end has a hole therethrough sized and adapted to engage an object, such as a nut. The hole is in communication with an opening for enabling the wrench to be positioned on a line, tubing, or the like by sliding the line through the opening and into the hole. The hole of the wrench end has a multi-sided inside periphery, preferably corresponding to an outside periphery of the object, which contacts the object for gripping the object during use of the wrench. The tool body has a protuberance sized and adapted to be disposed within the opening of the wrench end for providing an additional side of the multi-sided inside periphery for contact with the object. The tool body has a hole for receiving a tool, such as a torque-applying tool, for manipulating the wrench during tightening and loosening of the object.