4 Pack Black Stackable Bed Risers. 3 inch height lift. Material: ABS plastic. Size: The External Size: 4-1/8"(W) x 4-1/8"(D) x 3-5/16"(H). The Internal Size: 3-1/4"(W) x 3-1/4"(D) x 1/2"(H). Packages: 4 pc Bed Risers