Blue Sea Systems Cable Clam Features: Perfect for antenna installation; Waterproof co-axial installation without removing connectors; Save the expense of removing and replacing connectors; Avoid poor connections from removing factory connectors; Screws are Stainless Steel; Seal Material is UV-Stabilized Buna-N Rubber; Body Material is Acetal; Connector Opening 0.68in (17.27) or .83in (20.95);