O'Neill Hyperfreak Fire 4/3mm+ Chest Zip Full Wetsuit The O'Neill HyperFreak Fire Series extends sessions in bone-chilling water with its next-gen TB4 Firewall neoprene, featuring graphene-infused, heat-retaining, durable fibers. Fluid Seam Welds and Fused Super Seal Cuffs ensure a watertight seal. TB4 and TB4X materials continue the HyperFreak legacy of unrivaled flexibility, warmth, and comfort. HyperFreak Fire is the ultimate in Fiery warmth. F.U.Z.E. Closure (Chest Zip) 360 degree Anti-Flush Barrier with Drainholes (F.U.Z.E.) Fused Super Seal Wrist and Ankle Cuffs Recycled Oyster Shells and Eco Carbon Black Infused Neoprene Recycled Dope-Dyed Yarn Liners Aqua Alpha Solvent Free Neoprene Lamination Recycled Krypto Armor Knee Padz Key Pocket with Loop Triple Glued and Blindstitched with Exterior Fluid Seam Weld Technology Front, Back, Thigh, Butt: TB4 Firewall Shoulder, Shin, Calf: TechnoButter 4 Entry, Sleeves: TechnoButter 4X PLUS (+) = 0.5mm Extra thickness for even more warmth TECHNOBUTTER 4 - TB4 builds on the legendary Technobutter 3, the next evolution of the jersey introduces recycled yarns infused with graphene for increased wear strength and heat retention. TECHNOBUTTER 4x - Technobutter 4x goes beyond the gooey stretch, and soft feel of TB3x. Recycled graphene fibers line the jersey allowing for incredible stretch with added strength and warmth retention, all with a new look. TB4 FIREWALL - Technobutter 4 Firewall utilizes the recycled graphene fibers in a light and soft thermal layer to create a fire hot feedback loop. As the body heat warms the graphene fibers, they conduct the heat back into the body.