The 100% organic cotton barrier cloth cover protects against dust mites and mold. It covers the entire mattress and closes with a brass zipper. Size Crib 28" x 52" The soft organic cotton fabric is more comfortable than other barrier cloths. Brass Zipper extends two thirds around the perimeter for east removal. The Cotton Barrier Cloth is fully machine washable and dryable. Specifications: 6" thick, 100% organic cotton fabric, thread count 250 & brass zipper.