Filters provide excellent oil vapour control, increased efficiency and better engine performance in street rod and racing. You will find a crank case breather on a generator or diesel power plant set. These are usually an engine with an alternator mounted on a frame with a fuel tank is called a generator as it generates useable electrical power. Used as emergency power and auxiliary power in the event of a power loss, installed as a permanent power protection system for business continuity. Alternative energy systems, in the event of a power outage. Fully automatic critical power systems which turn on if power if lost for true power continuity systems. Usually fuelled by diesel, hence the name, diesel generators.