The Mares SXS Second Stage is a high-performance regulator with an exceptionally compact techopolymer body for ultra low weight. SXS stands for Second eXtra Small and emphasizes the extreme lightness and compactness of this second stage model. The SXS second stage features an ambidextrous breathing design that can be used on either the right or left side and includes a lateral side exhaust for better visibility in all diving positions along with an easy-to-use soft purge button. The Mares second stages also route part of the gas from the second stage valve directly to the mouthpiece through a curved bypass tube that creates a swirling effect or vortex movement. The core of the vortex is a low pressure area that pulls the diaphragm down during the inhalation phase, resulting in a markedly sensitive and easy breathing regulator. This Vortex Assisted Design (VAD) allows for the feel of natural breathing; you do not have the uncomfortable feeling of air being excessively “injected” into your mouth that is typical for high-performance venturi assisted second stages. The VAD also minimizes potential cold-water free-flow due to freezing because the gas expansion inside the 2nd stage occurs in the bypass tube, rather than on the mechanical parts.