The MC9-SC/Compact Pro is designed to be used in cold water, making it versatile to be used anywhere on any trip. It combines a balanced diaphragm 1st stage with a Sealed Chamber (SC) cold water system and a light and compact second stage, which offers high performance in water with temperatures below 10° C | 50 F. The MC9-SC is the 1st stage with a super compensated membrane very modern but, at the same time, easy to maintain and very robust and reliable. The thickness of the body walls has been optimized to minimize its weight. A semi-flexible elastomer sheath protects the 1st stage from bumps and erosions. The HP seat is made of AISI316 stainless steel. Apart from the possibility of replacement in case of deterioration when performing maintenance, the composition of the seat, much harder than the traditional brass of the fixed seats, prolongs its useful life since it better resists the deforming action of the metallic particles that can be introduced coming from the bottle. Polyurethane valve with high mechanical resistance, to oils and hyperoxic mixtures. The hypercompensation of the mechanism guarantees a slight increase in the intermediate pressure as the pressure in the cylinder decreases. The regulator, therefore, provides its highest level of performance in the final phase of the dive, without a doubt the most critical. An advanced study of the internal air circulation and an exclusive distribution chamber that channels the air volume directly to the LP outlets have allowed pressure drop in forced breaths to a minimum level (0.5 BAR | 7.25 PSI), guaranteeing use with high benefits in any situation. The seal chamber is environmentally sealed, protecting it against icing in cold water and against contamination from particulate matter in silty conditions. Particularly effective hat-shaped filter inserted without the need for a circlip. It features 2 high-pressure and 4 low-pressure ports. The thread of the DIN version has been made of stainless steel instead of brass to guarantee greater resistance in the event of falls or blows. To achieve extremely high performance in low-temperature environments, the Compact Pro 2nd stage, in particular, is designed with a special Thermoconductive Thermoplastic Neopolymer that can transfer heat like metal while preserving the design flexibility, chemical resistance, and physical and mechanical properties of a conventional thermoplastic. That is, it makes it possible to drastically reduce the weight while delivering heat conductivity on a par with metal cases. Thanks to this material and a specially conceived safety valve, it can pass all the tests for use in cold water with flying colors. It is compact (6 cm | 2.4 in) and very light (153 g | 5.4 oz) which makes it ideal for traveling. Service pressure: 232 BAR | 3365 PSI. Calibration pressure: 10 BAR | 145 PSI. The regulator is completed with the Octopus Compact Pro which has the same features as the second stage but is yellow, like the hose, for being easily recognized underwater. The MC9-SC/Compact Pro Octopus Compact Pro is designed and manufactured in Italy by Cressi, an Italian brand pioneer in scuba diving, snorkeling, and swimming equipment since 1946. The product is covered by a 2-year limited warranty.