Our heavy duty microstop uses ball bearings for ultra smooth operation. The ball bearing design also makes it run much cooler than a standard microstop. Depth adjustable in 0.001″ increments with positive locking collar. Shaft travel is 9/32″. Attaches to any drill having a 1/4″ chuck. Uses standard 1/4-28 threaded cutters up to 1/2″ in diameter. Use with pilot cutters ATS-100- or ATS-120- listed separately. Rated at 10,000 RPM. Note: Cannot be used for steel – only aluminum and soft metals.