They go on top of the car seat and protect the car seat from getting soaked when accidents happen. (pottypatty.com)
While many booster seats simply sit on top of your car seat, some can be anchored down. (wetheparents.org)
The car seat shown here, the Chicco NextFit Zip convertible car seat, has a no - rethread harness that is operated by the orange button on top of the car seat shell. (thespruce.com)