An inventor wanted to install a device that somewhat restricted the exhaust flow on small lawn tractor engines. In order to prove the device did not create excessive back-pressures and adversely affect exhaust emissions CleanAir was asked to perform pressure testing before and after the device. A simple test protocol was discussed and negotiated with the EPA and testing performed over a very short period of time. The tests were inexpensive and successful and allowed the inventor to commercially market his device.