These pre-insulated hot shoes are manufactured from carbon steel and insulated with Firetemp® and Foamglas. Firetemp® is a structural insert designed to carry the load capacity of the pipe while Foamglas is fragile and can support temperatures of up to 900F. The hot shoes measure 19 long with the base of pipe at 6. They weigh between 58 lbs to 185 lbs. The pre-insulated shoes are designed to maintain the insulated pipes at a temperature for functionality.