Polaris Slingshot Maintenance
I hope this post puts the search for the correct universal, u-joint, propeller shaft universal to rest.
Mine: 2016.5, not welded in. Welded in info to follow.
I have measured all of the dimensions in both SAE and metric:
Cap width: 1.065 in / 27.05 mm
Cap height: 0.578 in / 14.68 mm