This adapter is suitable for use with STOLTCO powered anodes that have a spade connector located at the top of the anode (1/4in-wide flat metal), and is intended for use with all sizes of gas-heated tanks, and for use with electric tanks any size up to 4500w of heating. It will have a indication of working circuit at the GND connection making visibility easy at the side of the tank where it is grounded, rather than at the outlet. Please note: shipping will be via USPS Ground for this item. Please see other listings in store if your anode uses a barrel plug (hole with pin) connection type.