BRAD PENN Compressed Natural Gas Engine Oil is a multi-viscosity lubricant specifically designed for use in compressed natural gas (CNG)-fueled vehicles. It is recommended by the company for use in Detroit Diesel 50G and 60G Series natural gas-fueled engines; in Mack CNG (utilizing Cummins CNG engines); and in Cummins B, C and L-10 Series stationary and vehicular engines fueled by CNG.