5 1/2" x 7 1/2" with 3 studs on back for attaching purposes   5 1/2" x 7 1/2" with 3 studs removed
2 1/2" x 2 1/4" with clips 2 1/2" x 2 1/4" without clips
2 1/2" x 2 1/4" with double sided tape for attachment
 
7 5/8" x 5 3/4" for wire mesh baskets 5 1/2" x 7 1/2" for plastic bulk tubs