These models allow the open cover to rest lower against the spa for a slightly less-obstructed view. Depending on the mounting system, the Covermate II can be screw-mounted low on the spa, or simply slid underneath for spas with weaker skirts using the optional Understyle bracket system (sold sepereately). Requires only 18 inches of clearance behind the spa. Comes standard with a TowelMate accessory for hanging up to three towels right where you need them most. - 4 per case