RUBIA FLEET HD 300 is recommended for all turbocharged or naturally aspirated diesel engines of commercial vehicles ( buses, vans, pick ups, taxis and for all off road applications (public works, agriculture, navigation, rail road requiring API CF 4 performance This lubricant is well suited for all industrial vehicles operating under severe service conditions (high temperature, frequent stops). RUBIA FLEET HD 300 is specifically recommended for diesel engines from heavy duty to extremely heavy duty.