Seals Seals at the neck, wrists and ankles keep water from entering the wetsuit. Rolled smooth-skin seals do the best job, but standard smooth-skin seals are also effective, followed by O-ring seals. Many suits use nylon cuffs in place of seals, which are comfortable but don’t block water intrusion.

Seams Glued and blind stitched seams eliminate water seepage because the needle doesn’t go through the fabric. Flat-seam or flat-lock stitching is softer against the skin but allows water in, making it better suited for warm-water suits.

Materials Modern high-stretch neoprene increases comfort and flexibility. Traditional neoprene is stiffer but resists compression better. Many suits use both types: compression-resistant neoprene for its thermal advantages, and strategically placed, anatomically shaped high-stretch panels to address the flexibility issue.

Zippers A high-quality zipper backed by a smooth-skin sealing system creates a water-blocking barrier that can’t be beat. Some suits employ zippers with overlapping teeth designed to reduce water seepage even further