Two adapters offered: Tapered spline adapter for the early Chevy's with this tapered spline and 10-32 thread. 1/4” adapter fits most universal wiper motors with 1/4” or 6mm motor shaft. Both adapters have an outside diameter of 1/2”. Price each.
These must be purchased in addition to the Wiper Arms unless you have the 1/2" knurl on your wiper motors.