ENGLISH Size of Mattress and Foundation This bed is designed to use a mattress size 74”75” long and 37½”-38½” wide with twinsize; 52½”-53½” wide with fullsize. Ensure thickness of mattressand foundation combined does not exceed 10” on upper and lower bunk and mattressis at least 5” below upper edge of guard rail. SAFETY WA RNINGS 1. Follow the information on the warnings appearing onthe upper bunk bed end structure and on the car ton. Do not remove warning label from bed. 2.