Seamless Shoulders: one single piece of 39 cell 1.5mm Yamamoto neoprene drastically improves flexibility and reduces fatigue throughout your entire stroke. Combined with 1.5mm underarm panels, you'll find no resistance while swimming regardless of whether your arms are up, down or anywhere in between..Improved Neckline: A lower, more comfortable neck design improves comfort and minimizes chafing without compromising the seal to prevent water entry..Hip Drive: Building off the Helix design, we've narrowed the center panel on the upper body and extended the side panels to maximize your natural body rotation in order to generate more power, resulting in more speed..Reactive Stretch Technology (RST): thinner 2mm neoprene paired with the most flexible jersey liner around the back and shoulders produce greater mobility and reach from the shoulders, reducing fatigue and increasing distance per stroke..S-Flex Side Panels: Thin 3mm side panels improve the ease of getting into the suit and promote better body position while swimming without sacrificing buoyancy..Quick Exit Legs: 1.5mm thin leg panels make it easy to get out of the suit after your swim, decreasing your transition times. Reinforced seam taping allows you to trim the legs if needed..Premium Yamamoto Neoprene: This wetsuit uses 39 cell Yamamoto neoprene which offers excellent flexibility and durability. SCS coating on the entire suit increases the hydrophobic properties (think more speed) and makes the neoprene more durable. Sourced from limestone, versus petroleum, it is the most eco friendly option available..Flexibility is Key: flexibility isn't based only on the quality and thickness of the neoprene. We use high quality super stretch and ultra stretch jersey liners throughout the Reaction to ensure the ultimate flexibility throughout the suit.