http://www.cat.com/en_GB/products/new/equipment/dozers/medium-dozers/1000004501.html. The Cat® D6N dozer is a game-changer when it comes to customer value. The new dozer is easier to operate, up to 15% more fuel efficient and up to 10% more productive. And, it's also the first tractor in its size class to offer advanced GRADE technologies as standard equipment. The D6N meets US EPA Tier 4 Final emission standards.