The external material is manufactured from a fully waterproof and durable polyester fabric with a lid securely closed by a zip along 3 sides. The top, bottom, base and handle surface are internally reinforced with solid plastic board to provide additional strength. The internal surfaces of the case are fully lined and the lid on the KaiserOne and KaiserFour includes a full size zipped pocket. The handle is sewn and riveted, and there is a strong fully adjustable shoulder strap with pad too.