These high-quality, heavy-duty universal joints are manufactured to Military Specification MS-20271. Their strong yet compact, thin wall construction allows them to fit into tight spots. Each joint is permanently lubricated and covered with a silicone rubber boot to exclude dirt. They are designed for cross-bolting, pinning, or welding to a close fitting shaft or torque tube. (Welding must be done carefully to prevent heat damage.) Maximum operation angle 30°. These joints are made in the USA and tested to meet or exceed Mil Spec MIL-J-6193 and MS20271 standards. Dimensions and Specifications for MS20271-B6: Bore Size (Inside Diameter): 0.250 inch (1/4 inch) Bore Depth: 0.500 inch Sleeve Outside Diameter: 0.372 inch Minimum Exposed Sleeve Length: 0.563 inch Maximum Cover Diameter: 0.781 inch Overall Length: 2.00 inch Minimum Ultimate Static Torque (at 0 degree angle): 200 Lbs.-in (22.6 N-m)