Many cities have banned the use of gasoline fueled commercial mowers before 1pm on “Ozone Action Days.” The Ferris Propane Powered IS® 3100Z meets all emission requirements by the Environmental Protection Agency. Propane power paired with Ferris’ patented suspension technology makes this machine an attractive package! Model Engine Deck IS3100ZBVP3261 895cc Vanguard BIG BLOCK Propane* 61" IS3100ZBVP3272 895cc Vanguard BIG BLOCK Propane* 72"