Blu Smooth MK1.2 2mm Neoprene Swim Jacket The MK1.2 sleeved top is designed to be worn over the MK1.2 longjohn. It can however also worn separately with swimming trunks for open water swimming and numerous other watersports. It is made entirely from 2mm Yamamoto #38 neoprene with an SCS coating and a super stretch inner lining. It suppleness and body hugging qualities make it not only extremely flexible but also lightweight and warm. It also features a low and comfortable neckline without the discomfort of a zip. This makes breathing easier, eliminates choking and significantly reduces chaffing. Lifting your head to look forward is also much easier as there is no pressure from a zip in the collar. Features: - 2mm Yamamoto #38 neoprene with SCS coating. Super-stretch inner lining