Used approximately 24 sqft surface are. Southern heat exchanger approximately 8" diameter X 36" long. Stainless steel tubes rated Full Vacuum at 250 degrees F. Approximately 3/4" Tubes stainless steel . Heads stainless steel. Carbon steel shell rated 10 psi @ 250 degrees F. Vertical design. Serial Number 86-396. Built 1987. Lug mounted. Southern Heat Exchanger.