Medium density. Urethane mold. Firm for flat surfaces. Soft for curved surfaces. 5/8" x 11 thread Medium edge urethane molded pad that is firm enough for flat surfaces, yet soft enough for curved surfaces. Hook face for loop backed sandpaper. Use with abrasive grits of 120-240. More durable and lasts longer than bonded pads. 5/8" x 11 thread. Maximum rpm 4800.