The MK21/G260 is a high performance reg system on steroids. It may be positioned in the mid-range of SCUBAPRO's regulator lineup, but it behaves like a front-runner with its ability to handle any diving scenario with power to spare.
The MK21 is SCUBAPRO's most compact balanced-piston first stage. Smaller and lighter than the MK25, it uses a smaller piston but it delivers the same level of breathing performance, no matter how hard you're breathing, how deep you're diving or what your pressure gauge reads. The MK21 also provides exceptional resistance to freezing due to the thermal exchange produced by the external fins on its polished chrome brass body.
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 G260 is the most imitated air balanced second stage design of all time. First introduced in 1986 as the G250, it was the first regulator to introduce an adjustable Venturi Initiated Vacuum Assist (VIVA). Today's modern version features metal components (inlet tube, orifice, inhalation control knob and hose connector) for excellent cold-water performance. It also offers a left-right hose attachment option, making it a great choice for tech diving configurations.
When you put them together you get a super-charged breathing system that's surprisingly affordable. It's a proven performer for all types of diving, but where the MK21/G260 really excels is in cold-water diving scenarios and technical applications.