Developed in response to the needs of the most discriminating athletes, the new M:2 features top of the line neoprene, Air Dome Chest/torso, Profile Design's proprietary patterning and collar and YKK reverse zipper for quick transitions. Designed with Yamamoto's patented limestone-based formula, which is lightweight and durable, with uniformly sized nitrogen filled cells for superior buoyancy and flexibility. Features: - 2014 Model - 4.0mm Air Dome SCS-Nano Chest/Torso: Air trapped in the perforated middle layer improves buoyancy over a solid panel. Ari Dome is designed with a 2.0mm SCS-Nano outside layer, .5mm perforated cell middle and 1.5mm jersey lining inside. - Advanced Flexibility: Varying density panels allow unrestricted movement and improve arm rotation and flexion for the most efficient stroke. - Durability: Less prone to fingernail/overstretch tears than 5mm thick panels. Stronger seams nest to thinner areas. - Improved Collar Design: 1.0mm #40 shaped collar 2 layers, low profile, SCS Nano inside and out. Aplix hook/loop back closure. - Legs: 4.0mm SCS Nano #39 front/back thighs - 3.0mm SCS Nano #39 Front/Back calves - 3.0mm ribbed back knee comfort panel - 2.5mm ribbed calf speed slice - Back: 2.5mm center floating zipper panel, 3.0 side back - Improved low back fit, upper back flexibility - YKK Reverse zipper - Construction: Glued, blind-stitched, and reinforced seams - Materials: Yamamoto #39 and #40 Neoprene: 100% sponge rubber laminated to nylon or polyester jersey