Combi Kobuk Highback Booster The Combi Kobuk Highback Booster is an extremely versatile booster as it can be used with or without the backrest. It helps to keep the child safe it he or she's too big for the car seat but not quite big enough for the seat belt. It's similar to the Graco Turbobooster in that it can be used backless or with a back, but unlike the Turbobooster, it features side impact protection that is enhanced to protect the child. The Graco Kobuk Booster also features two type