Ease of breathing is the essence of this reg system and it looks good too. The high performance MK25/S600 reg system is known for its low work of breathing and tremendous reserve capacity. Year after year, in successive independent tests, it has consistently ranked as one of the top-performing regs on the market. Synonymous with SCUBAPRO quality and unbeatable engineering, the MK25/S600 DEEP BUE is the preferred combo of professionals. In all water temperatures, in the most demanding dive conditions, this reg performs flawlessly, and it looks great doing it.