This is a two-piece design that is not connected in any way. It is low maintenance and is very durable. The company refers to this as COAT (Continuous Open Airway Therapy). It is an effective treatment for snoring, mild to moderate obstructive sleep apnea or severe sleep apnea when other treatment options have failed. It comes in two forms: one with clasps for good retention and one with a soft liner for those people who have numerous crowns or extensive dental work.