Built on a fortified Chevrolet Colorado platform, the H3 promises Hummer-grade toughness in a right-sized package. Compared to the H2, the H3 is 16.9 inches shorter in length, 6 inches shorter in height and 6.5 inches narrower. The H3 uses an electronically controlled 4WD system with a fully locking rear differential, traction control, underbody shielding, and GM's StabiliTrak vehicle stability enhancement system. H3 offers two tire packages, a Goodyear 32-inch all-terrain tire and Bridgestone 33-inch, both larger than any other midsize SUV. Interior notables include available heated leather seats, a large electric sliding sunroof, DVD-based navigation, and numerous customized accessories. Powertrain is a 3.5L/220-hp I-5 with a choice of manual or automatic transmission. Peak fuel economy is 20 mpg.