IST Sports' flagship regulator, the R410, unites the R4 balanced diaphragm first stage with the O-10 pneumatically balanced second stage. The R4, available in either yoke or din, is a sharp-looking rig, with gold port plugs and gold accent trim. The balanced diaphragm design keeps the intermediate pressure steady, so it performs at its best no matter what conditions you're diving in.
The O10 has been calibrated to pair with the R4 to provide excellent breathability and consistent air delivery regardless of tank pressure, depth, or diving conditions. It has a built-in heat exchanger for cold water diving, as well as a breathing resistance knob and a pre-dive switch to control surface freeflows. In recent ScubaLab reg tests the R410 delivered stellar performance on the breathing machine especially at the test level that represents recreational diving depths. It also held its own when pushed to extremes. In ocean tests, the reg proved to be a dry, easy breather in all swimming positions. And the extra-wide exhaust tee did a good job of diverting exhaust bubbles from divers' fields of vision.
The bottom line: The R410 is a stylish reg with good performance attributes.