The Marshall Excelsior 2-Stage Auto-Changeover LP Regulator allows you to hook up 2 Propane tanks and the regulator automatically switches over to the second tank once the first one runs out (and vice versa). The indicator changes color to let you know when a tank has been depleted and needs to be refilled. This also includes Dual 18" LP Hoses that fit current ACME Type-I LP cylinder connections. Made by Fairview Fittings, these hoses are made to work with both liquid propane and natural gas.