Eraser Wheel has serrations for improved cooling effect air flow.
Dynabrade surface grinding wheel has a diameter of 4 in. The quick change attachment allows for easy mounting to the tool or pad. In addition to the other aspects of these parts, another important component of these is the thickness. This Dynabrade part is 1 1/4 in thick. All abrasive products that rotate or spin, such as the ones in this category, have a maximum speed at which you can run them. This Dynabrade surface grinding wheel can be run at a maximum speed of 4000 RPMs.

Dynabrade 53270 7" (180 mm) Dia. Right-Angle Disc Sander
3M 87449 Silver Depressed Center Grinding Wheel, T27 Quick Change, 9 in x 1/4 in x 5/8-11 Center Hub Thread, 7010409732, 20 per case
3M™ 07012, Supplied Air Hose W-9435-100/07012(AAD), 100 ft, 3/8 in ID, Industrial Interchange Fittings, High Pressure, 7000005375, 1 EA/Case
3M™ 72013, Adapter 529-04-50, 110-120 VAC, 7000131705, 1 EA/Case
3M 29611, 641WY 1/4" X 24", 100 Mesh Diamond Cloth Belt, 7010534832
3M 33780, 641WY 1/4" X 24", 400 Mesh Diamond Cloth Belt, 7010534915
3M™ 94275, Versaflo™ Gold Coated Tinted Over-Visor with UV/IR Protection M-967N, 70071696879, 1 EA/Case
3M 27814, Stikit Paper Refill Roll 426U, 2-1/2 in x 100 in 240 A-weight, 7000045200
3M™ 37018, Supplied Air Respirator Vortex Cooling Assembly V-100/37018(AAD), 70070799013, 1 EA/Case
3M™ 72787, Calibration Kit 529-04-48, Large, 7000052154, 1 EA/Case
3M 27819, Stikit Paper Refill Roll 426U, 3-1/4 in x 70 in 120 A-weight, 7000045203
3M 02019, Wetrodry Abrasive Sheet, 2500, 9 in x 11 in, 7100003693, 50 sheets per carton
Dynabrade 95821 Dynabrade Air Lube 10W/NR, 4oz Bottle 
