Flush Mounts, 3/4'' diameter lamps to vehicle with snap fit, no screws required Suitable for PC requirements when using LED PC rated/combination lamps Sealing grommets secure lamps to vehicle, while assuring a 99.9 percent leak-proof seal Chrome plated flange improves the appearance on vehicle Security ring can be installed onto flange mount installations to prevent lamps from theft (US Patent 7,572,043)