8'' drive, 6'' idler, 3600 rpm, 7500 fpm, horizontal flip, over center cam belt release, two tool pockets, the 1'' holes are there for lightening, cleaning, and the lower front one will allow me to attach a 16'' wheel in the future. all main parts on the grinder including guards, pivot pins, tracking knob, belt release handle, and idler axle are stainless. this will be mostly for surface grinding. im sending my 7 1/2'' x 2 1/2'' wheel to contact rubber soon to get 90 duro serrated and become a 9 1/2'' wheel.