Thule Chariot Seat Liner

"The Thule Chariot Seat Pad is the perfect addition to your bike trailer to take your child's comfort to the next level. This pad offers additional padding specifically designed to maximize seating comfort while you are out and about with your child. Thanks to the integrated space for the bike helmet, your child can wear the helmet comfortably without compromising comfort while riding."
"Installing the seat cover is extremely easy and allows you to quickly remove and reattach the cover. This makes cleaning much easier, as the cover is machine washable at 30 degrees. This keeps the interior of your trailer clean and hygienic at all times. The Thule Chariot seat cover is compatible with a wide range of Thule Chariot models, including the Thule Chariot Cross 2, Sport 2, Sport, Cross, Lite, Courier and Coaster XT."
"This seat cover is not only practical, but also extremely functional, as it has been specially designed for use when cycling. It is waterand dirt-repellent, which means it will perform reliably even in unforeseen weather conditions or on adventurous rides."