S/n-07-68871-1, copper tubes. Brass manifolds, fabricated carbon steel casing and baseplate. Maximum allowable working conditions: 85 PSI at 400° F (shell) and 200 PSI at 400° F (tube). Unit has been hydro tested to 115 PSI (shell) and 260 PSI (tube). Connection sizes are 2.5" inside coil and 2" outside coil. Unit is in unused condition!