Necessary
"This fits well and is necessary to use the seat (not the baby attachment) without sliding off. For my 2 year old who has now transitioned to the seat, I am confident that the inlay will make it more comfortable and stable. This washes easily in the washing machine and has remained looking good. I have not tried the tumble dryer on this, only air dried. The only negative is that I only needed the inlay for the seat and not the baby seat attachment, but both inlays arrived in the package."