The IS® 5100Z series of diesel powered zero-turn mowers features an impressive complement of comfort, performance and convenience. Easy access to service areas, impressive horsepower, enhanced operator comfort and increased performance all contribute to the time this machine will save you. When it comes to commercial lawnmowers, this is truly the ultimate riding and cutting machine. Model Engine Deck IS5100ZC33D61 33.5 gross HP^ Caterpillar 61" IS5100ZC33D w/ 5100/61R 33.5 gross HP^ Caterpillar 61" Rear Deck IS5100ZC33D w/ 5100/72 33.5 gross HP^ Caterpillar 72" IS5100ZC33D w/ 5100/72R 33.5 gross HP^ Caterpillar 72" Rear Deck Model Engine Deck IS5100ZC33D61 33.5 gross HP^ Caterpillar  61" IS5100ZC33D w/ 5100/61R 33.5 gross HP^ Caterpillar 61" Rear Deck IS5100ZC33D w/ 5100/72R 33.5 gross HP^ Caterpillar 72" Rear Deck