The Philips Respironics DreamWear comes standard with the medium frame in the package. Some people have found that the medium is not suitable and may need to go for the larger or smaller frame. The key is the frame needs to line up at the top of the head with the tubing connector between both ears. If this is not possible you may need an alternative size. The sizing of the frame is written near the tubing connector on the top of the frame near the elbow.