Natural Gas Integral Compressor Hour Meter Reads: N/a; Concrete/steel Skid Unit Runs & Operates As It Should?: Yes; Psi: 1250; (muffler 11 X 22" Exhaust Pipe 10 X 1 Included) AJAX-cooper Engine, 60 Hp 5-1/4" X 3- 3/4" X 8" Bore.