Every Atlantic HiLine Tower is built around our exclusive ATL 8 (pat pending) extrusion system. This system allows the construction of completely finished hardtops which can be retrofitted to existing factory installed arches, or can be incorporated into complete one piece structures such as self-supporting hardtops or even tuna towers. HiLine hardtops feature powdercoating of the hardtop structure to match the inner and outer fiberglass surfaces, giving the appearance of a full molded top, but much lighter in weight.