- Attractive burgundy cardstock storage box. Holds twenty-six PSA graded card slabs. Special slotted sides keep your slabs accessible. Exterior Dimensions: 3 5/8 x 5 7/8 x 14 1/8. Interior Dimensions: 5 3/8 x 3 1/8 x 13 3/4. The BCW Slotted Storage Box is a sturdy, attractive box designed to safely store your collectibles and at the same time offer the ability to easily access any one piece you desire. Currently, there are several reputable and well-used grading companies in the hobby like Professional Sports Authenticators (PSA). This box works great for storing and organizing your PSA slabs.