Zone3 Neoprene Heat Tech Swim Socks These innovative swimming socks are some of the warmest available on the market, perfect for those who suffer from cold feet or swim through the spring, autumn or winter. These booties are 3.5mm so slightly thicker than Zone3's standard socks and come complete with a titanium lining to reflect the body's heat and improve warmth. They are made from high-stretch material to ensure a great fit and flexibility during the swim. The seams are glued, double blind stitched and then liquid sealed on the external side to help ensure they are watertight and durable. The Zone3 socks also have a unique Smoothskin Waterblock system at the top to help keep water ingress to a minimum as well as a Velcro strap to help minimise any water entry. They also feature a durable gripped sole to enable walking to and from the water. Feature includes: Fit all your kit: Some of the warmest and most water tights socks on the market. High stretch 3.5mm neoprene with Titanium lining for warmth. Liquid seal finish and Smoothskin closure system to reduce water entry. Increased length with Velcro closure to ensure the socks stay in place.