These seats offer a harness for children 20-40 lbs and then you can use a seatbelt when the child reaches 40 lbs and is at least 35” tall. You can remove the harness when child reaches approximately 30 to 40 pounds. (Recommended that the child is at least age 3-4) and use as booster up to 80 pounds or upper weight limit listed on seat.
Tips for using the combination booster seat and properly restraining your child:
When used as a forward facing seat:
Place harness straps at or above child's shoulders. Forward facing seats have several slots; always choose the slots closest to your child's shoulders.
Place chest clip across the child's chest at armpit level to keep harness straps in place and keep them snug.
When your child reaches upper weight limit of seat with harness (40 pounds) remove harness and use as a belt-positioning booster seat with the vehicle's lap and shoulder belt (see tips for properly restrained child in a belt-positioning booster seat.)