The phrase "additional inserts" refers to extra things or items that are added or put into something else.
Sentences with «additional inserts»
This shell, in combination with the fleece topped hemp booster, could likely work on its own for newborns and save the bulky additional insert for later. (themamaknows.com)
You can also add additional inserts to the diaper to make it more absorbent. (pootersdiapers.com)
It fits newborns without additional inserts and adjusts to your child's height with the help of a convenient measuring chart. (pregnancymagazine.com)