Burnewiin mounts are designed to blend into boat gunwales and horizontal surfaces in the same way as traditional flush mounted rod holders. The difference is Burnewiin mounts are designed to hold multiple accessories in addition to rod holders. This allows multiple configurations and combinations of accessories based on how you are using your boat at any given time. The GM400 mounts are made of tough, glass-reinforced nylon. The GM650 Gunwale Mount is constructed of investment cast 316 stainless steel. When selecting the Burnewiin mount that will best suit your needs, consider the mount compatibility of your accessories and future boating plans. GM400 and GM600 mounts have the same mounting pattern and are interchangeable if necessary. Each mount includes an integrated, low profile lock to hold accessories fast and a built-in accessory hitching loop to fasten rod leashes, Burnewiin towels, or other appropriate accessories.