Type 1.5 pound crab pot zinc anode that ties on. These anodes are manufactured in bundles of 5 that are designed to break apart. Make sure you have a RotoMetals zinc Sacrificial anode attached to your weight bar and prevent corroding and prevent the scale or "slag" from forming. This will save you time and eliminate the need to hammer your weight bar between and during crab season. The anode also helps "cool" the trap down due to the Electrolysis in the water, thus making it more appealing to enter.