Flapper Adapter 5/8 UNC Thread with 1/4" Collet 5/8 x 11 Thread. Turn Your Grinder Into A Rotary Tool Allows you to mount any wheel with a 1/4" shaft onto your angle grinder. 303 Stainless body with Tool Steel Collets, 1/4" Collet, and Nut. Use your Flapper Wheels, Carbide Burrs, Cutoff wheels or Polishing wheels. Made In USA