Ultrathermic Cutting Rods may be used with a maximum of 150 amps to assist in the burning process but have no electrical requirement. Once ignited, they continue to burn as long as oxygen is supplied or until the rod is consumed. Broco® Underwater Ultrathermic Cutting Rods are available in 1/4 inch and 3/8 inch diameters. Standard length is 18 inches. Broco® offers 36 inch Ultrathermic Cutting Rods for heavier jobs allowing more burn time between rod changes.