GESi mufflers use the Dry Selective Catalyst (DSC) system to reduce up to 99% of the CO, HC, and NOx emitted by commercial fuel-burning engines. DSC technology can be installed on any rotary, spark, or compression engine running on gasoline, propane, natural gas, diesel, or biodiesel fuels to reduce up to 99% of emissions. Bartell Morrison. 866-501-1683.