What Our Gearhead(R) Experts Are Saying:"The Spring Fever shares the same natural rubber blend and Upcycler Pro Stretch construction as the Salty Dayz but goes with a back zip entry instead of chest zip. That's a meaningful difference for a lot of surfers. Back zip gets on and off faster, which matters when you're rushing to catch a window or wrangling gear in a parking lot. You trade a small amount of water seal at the neck for that convenience, but in mild spring conditions that's rarely an issue. The flatlock stitching and silicone lining are the same quality throughout. A well-built suit for surfers who prioritize easy entry."The Billabong Spring Fever 2mm Back Zip Spring Wetsuit is for the surfer who wants to spend less time suiting up and more time in the water. The back zip entry pulls on and off faster than a chest zip, which adds up across early morning sessions and afternoon windows when the tide is right and the clock isn't. The same natural Hevea rubber blend as the Salty Dayz runs through the 2mm construction, blended with soy bean oil for a neoprene that flexes more naturally through a paddle than conventional synthetic foam. Upcycler Pro Stretch throughout keeps the suit moving in every direction without restriction, backed by a silicone stretch lining that sits comfortably against the skin from the first session to the hundredth. Flatlock stitching eliminates seam friction across a full day in the water, and the 87% recycled polyester and 13% recycled elastane exterior keeps the sustainability credentials honest. Part of the Surf Capsule Natural collection, the Spring Fever is a straightforward suit built on materials that are anything but.