The BMW 3 Series employs a lightweight aerospace 6061 T6 "drawn" (this is a shaping process which retains structural integrity) aluminum tube with each end having a mandrel bend of a 4" radius. This tubing is used inside another high-density foam tube with a half-inch wall thickness.

The assembly constitutes a very lightweight, sturdy and upholstery-friendly Support Cradle that supports the hardtop securely from beneath, avoiding paint and weather stripping. The hardtop is balanced with a connected harness of nylon seat belt webbing that is sewn with heavy-duty polyester thread to the required length. Your hardtop can be suspended indefinitely. All hoists include your choice of lifting systems: the manual pulley, the brake winch or the motor winch.