Proto has introduced a new line of ratcheting wrenches with spline box ends, in Metric and English versions. The new tools are part of a 95-SKU line extension, and include double-end box wrenches and combination wrenches. All have a ratcheting spline box head that lets users apply or remove fasteners without having to continually remove and re-attach the wrench. The combination wrench has an open end featuring the Proto® patented Anti-Slip Design (ASD). One of the greatest strengths of spline wrenches is their versatility. In addition to turning spline fasteners, they will do everything that a 12-point box wrench will do. Metric versions will even turn External Torx® fasteners. A spline head is also more effective than a standard wrench at turning a rounded or damaged 12-point fastener. That's because the spline head is designed to move the load away from the fastener corners, spreading it over the flat areas. This increases the contact area between the surface of the wrench and the surface of the fastener, letting the user apply more force without rounding or scoring the fastener. The design also reduces the chance of knuckle injury, and lowers concerns about Foreign Object Damage (FOD) to equipment. And, of course, spline wrenches are the only wrenches that will turn the high tensile strength spline fasteners that are common where high performance torque is needed: on military and commercial aircraft, in heavy machinery applications, and in some automotive and industrial settings. Like the spline wrench, the ASD open end on the combination wrench is also designed to increase the torque that the user can apply to the fastener. It features a locking groove that keeps the wrench from slipping off of the fastener, as well as an arched profile that moves the turning force away from the fastener corners. Unlike other slip-resistant designs, the Proto® ASD has an arched profile that is designed to help minimize the possibility of fastener damage or FOD. The new ratcheting box-head spline wrenches come in a distinctive color combination that helps users differentiate them other tools. Instead of being bright silver with a black ratcheting end, they're bright black with a silver ratcheting end.