Hummer H1 is a civilian off-road vehicle based on the M998 Humvee, which was created by AM General. The Hummer H1 was produced from 1992 to 2006, and was the first of what became the Hummer line. The H1 was available as a two-door hardtop, a four-door hardtop, and a four-door convertible. It featured a powerful 6.5-liter V8 diesel engine, four-wheel drive, and heavy-duty suspension. The Hummer H1's distinctive design, with its large tires and boxy shape, made it popular with off-road enthusiasts.