TEKTON WRN77003 Extra Long Flex-Head Ratcheting Box End Wrench, 5/16-Inch x 3/8-Inch Extra long beam offers extreme reach and loads of leverage Box end heads pivot 180 degrees to easily get around obstructions 6-point box ends snugly fit hex-shaped fastener heads and resist slipping off while you work Openings are designed to grip flat sides of fastener heads, not corners, to prevent round-off 72-tooth ratchet gears need only a 5-degree working swing arc