2 Tank Holder with Single Suction Cup MountMax Holding System's tank racks are made out of a white powder coated aluminum track, durable polypropylene adjustable brackets, heavy duty suction cups, sturdy weather resistant plastic handles with easy to release latches. These systems securely hold your tanks and spear guns vertical while the plastic handles can be used for hanging dive equipment such as masks and fins. Industrial suction mounts. To mount this speargun holder you only need a 5