The helmet people recommended this to us. There is a hole cut out so there is less pressure at the back of the head. We use it in his swing, car seat, bouncer, on the ground when he plays on his mat and at night when he sleeps (although the tag says not to use it for sleep, we think its ok at Charlie's age). You can purchase it at target.com or pottery barn kids. We wish we had known about this sooner!