The Cressi MC5 Steel Scuba Regulator combines Cressi’s middle-of-the-road MC5 first stage with its steel Ellipse second stage (or mouthpiece). Relative to the non-steel version of the MC5 package, this is a heavier-yet-tougher machine. The extra steel fittings make the second stage more durable than a mostly plastic mouthpiece, but at the cost of the total package weighing almost two pounds. That might not matter for traveling divers, since it is a matter of several extra ounces in the dive bag, but it does matter in terms of jaw fatigue. While much lighter than other steel regulators, divers who are putting in two to four dives per day, day after day and are not used to that schedule will find their mouth and jaw bone-tired at the end of the day from supporting that extra metal of the MC5 Steel. Still, that is the price to be paid for a mouthpiece that can take a beating in the back of a van or on a dive boat.
Breathing performance tests for scuba regulators are performed on what is called an ANSTI machine, which tests how well the regulator delivers air under different depths and at different levels of demand (i.e. how hard the diver is breathing). The Cressi MC5 Steel passed all the ANSTI tests for recreational diving, so divers can count on it to deliver plenty of air under normal diving conditions. Field testing revealed that the regulator stays dry under all swimming positions, such as going upside down in order to look under a crevasse. The second stage also earned plaudits for clearing easily and with only a single light puff of air. The device is also compatible with Nitrox, with a gas mix of up to 40% oxygen.
Another big plus is the top-mounted Venturi lever. If a diver jumps into the water with the second stage in a bad position and starts free-flowing air, this lever is easy to find and offers a quick shut-off switch.
On the downside, reviewers considered the MC5 Steel to be a noisy regulator. Divers who like serene, quiet bliss underwater will not appreciate the loud stream of bubbles and Vader-like inhalations. The regulator also comes with only one high-pressure and three low-pressure ports. That represents the bare minimum of ports, and even for a middling regulator that number is not much. It limits flexibility in choosing the mounting positions for regulator equipment onto and absolutely prohibits putting any accessories onto the machine. The MC5 Steel was meant to mount a main second stage, a back-up second stage (the yellow mouthpiece or octopus), a gauge console and hook-up to a BCD, and that’s it.
Overall, the Cressi MC5 Steel is a solid, dependable regulator offered at a reasonable price. It offers divers some growth potential in the form of its Nitrox capability, but the lack of extra ports means sticking to the basic scuba kit.