The Prolimit Innersystem Chillvest Classic Neoprene Lycra is a 0.5mm sleeveless neoprene top to wear as a first layer under the wetsuit. Ideal for cold water conditions where you want extra warmth. You will be surprised by the warmth that this garment can give with only 0.5 mm. It also serves as a neoprene vest for warm water conditions, to lengthen the sessions without getting cold and protect from scratches and the sun.