Moisture proof sealing ring around the shaft to keep out spray and make it seat firmly in the outlet "ON" indicating LED Strain relief Built-in 10 Amp fuse Designed to withstand the rigors of wet environments and constant vibration Large contact surfaces for good electrical connection Twist lock system—plug locks securely into socket Internal strain relief and cord seal Nickel plated copper alloy used for all current carrying components Front panel, rear panel, or surface mount