What is "underjams"

UnderJams are a pull on style diaper used as a way of managing bedwetting that are made by Pampers. They are similar to GoodNites. "UnderJams" claim to be softer and quieter than GoodNites, and even though the package states that they will only fit children up to 85 lbs. Also, because of their low waist, they are hardly visible under pajamas.