http://www.aikencolon.com/retrotec-us242-du200-ductester-air-duct-leakage-test-system The Retrotec US 242 features a calibrated Model 200 fan, Flex-Duct & the DM32 gauge. Retrotec's US242 includes everything you require in order to measure air duct leakage. Made for air duct testing Retrotec's DucTester is specifically designed to test ducts & tight enclosures and features over 3x the power needed to test even the leakiest duct systems to current standards.