Leaderboard

A true demand valve supplies o2 automatically as the user inhales. Kinda why it's called a demand valve...it supplies gas....on demand. Most also have the button as well. I would assume that a button only valve would be more of a resuscitation unit.....As the the OP's question about difficulty exhaling with a cluster mask...that usually happens with one that's been used a while and needs cleaning. If it's new...it could have a defective valve....be assembled incorrectly or the valve is stuck as a dirty one might be. Hard to say without examination. If it's defective DJ would undoubtedlydo what's needed to solve the problem.