The entire front of the Orca S4 is SCS-coated Yamamoto #39 neoprene. Both 3 and 4 millimeter thick neoprene are used with the thicker panel being located in the bottom half of the suit below the seam across your belly button. This is a well conceived design since most swimmers need more floatation in the legs, not the chest. It also makes sense for fitting. The middle 80% of triathletes probably need some additional room in the chest and torso of a suit. The best way to provide that room is not to do it with a bigger pattern, but with better fabric that conforms to the swimmer more precisely without letting water accumulate inside the suit during a long swim. Orca put nice quality Yamamto #39 3mm neoprene on this chest panel, a strong choice.