Pelican 1560M Mobility Case is the same as a 1560 case but with heavy-duty wheels designed for rough terrain. 10.2 diameter x 3.8cm wide (4" diameter x 1.5" wide) heavy duty polyurethane wheels with stainless steel bearings.Interior size (L X W X D) : 50.6 x 38 x 22.9 cm (19.92" x 14.98" x 9.00")Exterior size (L X W X D) : 60.4 x 46.6 x 30.7 cm (23.78" x 18.33" x 12.08")