Clamp-On Accessory: Fits: 1.660" Pipe, Mounts: Horizontal, Finish: Silver, Heavy duty Clamp-On brackets come ready to mount fixed antennas. These brackets are designed to fit standard size aluminum pipe. Constructed from marine grade aluminum, all brackets are anodized after fabrication for 100% anodized protection. These brackets come standard with bright silver anodized finish. Quickly attached or detached with only an Allen Wrench, they are the perfect retro-fit item.