The MC11SC first stage unlocks your next level of diving: You can dive deeper, colder, more streamlined. This first stage is a dry sealed, cold-water suitable hyperbalanced diaphragm system, power-packed into an ultra-compact size. SC stands for sealed chamber and only adds 30grams to the standart, warm water MC11, but additionally keeps its working components dry and clean, preserving lubrication and protecting them from corrosion, while the shockproof technopolymer protection helps to maintain this first stage to look "like new" for many years of diving.