Dynabrade® Depressed Center Wheel Grinder, Geared Heavy Duty, Tool/Kit: Bare Tool, 4 in Wheel dia, 3/8-24 Male, 12000 RPM, 0.4 hp, 23 scfm, 90 psi Air, 1/4 in NPT Air Inlet, Rear Load Exhaust Location, Safety-Lock Lever Throttle, 1/4 in Minimum Hose Size, Right Angle, 81 dB, 7-1/2 in L x 3 in H. Dynabrade® 52706 Geared Heavy Duty Depressed Center Wheel Grinder, 4 in dia Wheel, 3/8-24 Male Arbor/Shank, 0.4 hp