Armstrong 12-947A 1/2" Drive Universal Joint Maximum Operation Angle of 45 Degrees Unique Modified Ear Design Prevents Lock-Up at Extreme Angles, Allowing for Smooth, Continuous Operation Manufactured From High Alloy Steel Using the Most Up-To-Date Manufacturing Process and Heat Treat for Greater Strength and Durability Meets or Exceeds ASME B107.10M and US Federal Spec. GGG-W-641E