Same end on both sides here: 3/4"-20 spline. It's the one to grab when your shafts match.
- End 1: 3/4"-20 spline (code 21)
- End 2: 3/4"-20 spline (code 21)
Match your shaft splines against the ends listed in the specs before you order.
Howe Performance part number UJ-2121.