The Original Fire Rated Liquidator tank level indicator works with an external 2" guide pipe. Steel conduit works best. The indicator slides up and down on the outside of the pipe, and the stainless steel counterweight is contained inside it. Only the float is in contact with the liquid. The Australian Fire rated version of the Liquidator comes with stainless steel cable, brass pulleys, stainless steel counter-weight, polypropylene float, and steel mounting bracket.