Safety, comfort and convenience make an exceptional Harness-2-Booster Seat. At Britax, we're making safety cool - your child will enjoy a comfortable ride. This booster seat features the patented Britax SafeCell Impact Protection system which includes a steel frame, energy-absorbing base, V-shaped tether to minimize seat rotation and staged-release stitches that slow and reduce forward movement in the event of a crash. Britax designed the seat with 2 strong layers of side energy absorption; a deep foam-lined shell and head protection will shield your child from the most severe type of collision. The 9-position quick-adjust harness grows along with your child and it's easy to transition from a harness to a belt-positioning booster by tucking the buckles and straps within the seat. Harness-2-Booster Seat can be used in Harness Mode for children 2 years old and 25 to 90 lbs or in Booster Mode for children 40 to 120 lbs. Child standing height using the harness 30-58" and using booster mode 45-62". Dimensions minimum 19 W x 28 H x 21 D, maximum 19 W x 36 H x 21 D inches. Seat width 12". 9-Position harness slot heights 12.5" to 20.5". May not be compatible with all vehicles, see user guide.