he 2.5 mm thick Synergy neoprene swim sock is an insulating bootie for swimming, diving, kayaking, surfing and beach going. It has a silicone thread for durability and protection. The extended hose shaft has a smooth skin neoprene lining that creates a seal to reduce water intrusion. It is designed to fit neatly under your wetsuit pant leg, but can also be worn without a wetsuit. All seams are blind stitched, heat taped and chemically bonded.