I have owned 3 of these during the years that I have been diving. My opinion, rarely do they disappoint. These were popular in the 80’s time frame with recreation sport diving. Now in 2022 in “tech-diver circles” (rebreather groups, the discussion boards on websites) they are viewed as a recreational devices not really for use with normal tech applications such as deep, cavern, cave or wreck diving. I will say this Draeger builds quality products and the Dolphin is no exception. Just a great, fun and safe unit to dive. Even more fun is converting them to a full CCR unit that can be configured for pure O2 or a mixed gas unit.