Set of three 5 inch diameter brushes. Each oscillating accessory brush has a threaded 5/16x24 steel shaft to fit popular rotary polishing and DA machines including: PORTER-CABLE 7424XP, Meguiars G110v2 Polisher, Dynabrade 59040· Orbital Pneumatic-Random Orbit and similar electric and air operated dual action machines. The Black brush is very stiff for rust removal, paint stripping, and de-scaling where scatching is not an issue, The Red brush has stiff bristles for heavy duty scrubbing of flooring, concrete, and brisk. The Green brush has medium stiffness bristles for all purpose scrubbing of Tile and Grout, Bathroom surfaces, and stairs. Machine NOT included