FREE SHIPPING
This item qualifies for Free Shipping! Details.
But fear not - there is plenty to explore...
Shop all O'Neill Shop sale O'NeillMEMBERSHIP
Earn up to 10% back in rewards. Learn more. Join Free.
EASY RETURNS
Take up to a full year to return your item! See our Return Policy.
LOWEST PRICE GUARANTEE
Find a better price? We’ll beat it by 5%. See our Price Match Policy.
Gear up for cold water fun in the O'Neill 4/3 Psycho One Back Zip Wetsuit. Psycho One suits offer O'Neill's premium TechnoButter 3 neoprene in a lightweight, minimal seam-design package with a convenient back zip and super watertight Fluid Seam Welds. When the shoulder season surf is pumping and your warm-water setup just won't cut it, turn to the 4/3 Psycho One and get after it.
TechnoButter 3 – O'Neill's exclusive, maximum stretch, hydrophobic neoprene with featherlight ENVY foam rubber core. Ultimate warmth and comfort. Built to last.
Z.E.N. Back Zip – Zip (back) Entry System with free floating zipper panel and anti-flush barrier with drain hole keeps you warm and unrestricted.
Double Seal Collar – Fully adjustable glide-skin seal is comfortable and watertight.
Fluid Seam Weld – Sealed 8mm silicone-based urethane exterior with a triple-glued and blind stitched interior. Watertight, durable, and ultra flexible seam.
Minimal Seam Design – Insane flexibility, fit and durability using a unique design which utilizes larger panels and less seams.
Krypto Knee Padz
Plasma Wrist Seals
Aqua Alpha Solvent Free Neoprene Lamination