The lightness and portability of Markbass products is to some degree negated when heavy flight-cases are used. But when the musician transports his gear himself (in other words, outside of tour situations where the goods are transported by others), Markbass covers are a practical choice: lighter, less expensive, and still very protective. Fits AC 601 Markbass covers are made of the following materials: Outer layer: Polyester 600D x 600D PVC Padding material: PUR Foam 10 mm Lining material: Nylon 190T PU.