Specifications include, but are not limited to: 2.3.2 Conventional Units - Engine ahead of cab. 2.3.3 Tilt Cab Unit - Engine in, under or to rear of cab. Cab easily tilted or elevated to permit easy and complete access to engine. Secure, foolproof hold down lock on cab. Cab removable through use of springs, power, or other work saving means. Cab overall width at least 66 inches. 2.3.4 Forward Control Unit - Engine next to or behind operator's seat. Operator's seat elevated for step-in, step-out use. 2.3.5 Compact Unit - Engine next to conventional type operator's seat. 2.3.6 Five Man Cab Unit - Conventional type with sedan type cab, 3 or 4 doors with at least 2 doors on curb side. 2.3.7 Cab Step Height - First Riser: From ground to step or cab floor 26 inches maximum. For steps over 18 inches furnish an assist hand or grab bar. Second Riser: (If required) From step to cab floor 18 inches maximum. Not more than one outside first riser on tilt cab unit. 2.3.8 Driver's Compartment Bench type seat for at least two preferred, however, two bucket seats acceptable.