The Gator Cases GP-PC204 Large Quad Case is a hard polyethylene case that holds four connected drums. The wheeled case provides ease of movement when you arrive at a destination or are on your way to a gig. The case contains three handles as well as a firm strap closure. Rotational molding is a 3-stage heating process that results in evenness all around the edges of the case. The polyethylene material is inserted into a mold and then gradually rotated until the material sticks to the edges of the mold in an even pattern. Once cooled, this plastic material forms a strong bond that minimizes sagging and potential collapse.