15 Pcs/5 Box Aligner Chewy for Aligner,Orthodontic Chewers for Aligner Trays Seater Chewy, Silicone Orthodontic Chew Sticks with Storage Case

It’s plastic thingies your literally chew on during the day, especially when changing trays. Helps secure them snuggly on your teeth and helped a lot when teeth were not tracking properly. You can get some on Amazon (ie. https://a.co/d/0auFTnT1)