A HUMMER is hard to miss with that bold face and toothy seven-slot grille, a flat roof and square cabin with narrow windows that resemble a military bunker. The original H1 HUMMER, a civilized version of the military High Mobility Multipurpose Wheeled Vehicle, or Hum-Vee, comes from HUMMER's parent company, AM General. But General Motors has marketing rights to the HUMMER label and the first offspring of GM's HUMMER Division is a junior version of H1 named H2. For 2005 the H2 SUV spawns a four-door pickup variation tagged as H2 SUT, meaning sport-utility truck.

This is the original civilian version of the military Hum-Vee, and it brings awesome capability. Conformed as a four-door boxy sport-utility wagon or a four-door open-top wagon, the H1 shows significant enhancements for powertrain and cabin appointments. The turbo-diesel V8 engine, displacing 6.5 liters, now delivers 205 hp but huge torque of 440 lb.-ft. at only 1,800 rpm, and it connects to GM's Hydra-Matic 4L80-E electronically controlled four-speed automatic transmission. Heavy-duty four-wheel-drive (4WD) equipment goes into every H1 with sophisticated controls to automatically reduce tire spin on slippery terrain by braking a spinning wheel. In the cavernous four-seat cabin, H1 gets luxury goods with redesigned seats, fine leather upholstery and a revamped cockpit and dash design.

Think of the H2 SUV as a junior version of the H1 HUMMER. It has the boxy body of an H1 with a flat roof and four-door cabin, but the package is smaller and friendlier for navigating city streets. H2 rides on a modified version of the chassis of GM's Chevrolet Tahoe and GMC Yukon wagons, with mechanical components including a humongous 315-hp 6.0-liter V8 engine borrowed from full-size Chevrolet-GMC trucks. A broad track and extended wheelbase with brief overhangs and super-sized tires work to make the H2 exceptionally stable, and a high ground clearance with underbody skid-plate shielding ensures it can navigate rough off-road terrain.

Every H2 stocks a Borg-Warner two-speed electronically controlled full-time 4WD system. The system divides torque from the engine either 40/60 percent front-to-rear for running at speed with differentials unlocked or 50/50 percent with differentials locked. Riders in H2's spacious cabin rest on firm bolstered seats and encounter luxurious accommodations with optional leather upholstery and high-tech audio and navigation gear. The second-row bench holds up to three adults and an optional third-row jump seat, which can be folded or removed to expand rear cargo space, fits a teenager.

The newest HUMMER works as both wagon and truck, which explains the tag of sport-utility truck, or SUT. It's derived from the H2 SUV with similar powertrain and mechanical equipment. Where the H2 SUV shows an extended roofline and the boxed rear bay of a wagon, the H2 SUT differs by lopping off the roof to make way for an abbreviated truck bed, which is roughly four by three feet in size.

But there's more: The back wall of the SUT's cabin also works as a door -- it folds down and forms a generous extension of the truck box. With the back wall folded down, there's a flat cargo bay extending six feet to the tailgate for expanded cargo volume. With the wall raised and window up, the cabin is sealed off from the rear truck bed. You get a conventional cabin with two bucket seats up front and a three-person bench in back, followed by the Midgate sealer and the back unsheltered truck box. Extra equipment ranges from a rooftop light bar and dashboard DVD navigation system to special packages like the Adventure and Lux series.