Includes (4) - Genuine Ridgid part number 200202538 Plate & Cushion assembly. Fits Ridgid R2501 Random Orbit Sander. Each one measures approx 4-5/16" x 4-1/8" x 1/4" thick. Mounting hardware not included - Bolt pattern approx 2-1/16" x 2-5/8" on center. 10 Vent holes to pass dust through to dust collector.. Compatible with the following models: Ridgid R2501 Random Orbit Sander