3mm nylon II neoprene. Glued and blind stitched inside and out. YKK #10 Brass zipper. Low profile water sealing zipper design. Dual zipper pull loops. ZIPPER: YKK #10 brass zipper. Our unique zipper design utilizes dual rubber strips to additionally seal the zipper opening when closed, creating a water resistant closure. In addition, our low profile zipper flap folds over a closed zipper to further seal and secure the zipper in its closed position. The reinforced pull loop at the base of the zipper makes self-donning of the suit fast and easy.