(30) Clear & Black Wide Back Cassette Boxes #CABS15BC - 4-1/4" x 2-3/4" x 5/8" (Audio Tapes, Boxes) Standard 15.88mm Thick! (Appx .63") This is the same size that the majority of cassettes are sold in! Features 2 hubs to hold cassette in place, and an L-Card holder for papers!