The MK21's innovative "smart" hose layout comes with a standard cap with four low pressure ports angled (+/- 20º) to maximize hose routing. This standard cap can be replaced with an optional cap that offers four low pressure ports at more extreme angles (0°/30°) plus a fifth centralized high-flow low pressure port -- a useful configuration for technical diving.

The air balanced S560 second stage features a lightweight techno-polymer casing and comes with full user controls, including an inhalation effort adjustment knob and a Venturi-Initiated Vacuum Assist (VIVA) dive/pre-dive switch. It can be counted on to breathe dry and easy, regardless of depth or your position in the water.

The MK21/S560's size and weight make it an excellent choice for travel divers, its innovative fin design makes it a good cold-water performer, its "smart" hose layout is well-suited for some technical applications, and its overall ease of use, reliability and price make it the must-have reg system for recreational divers of all skill levels.