Neoprene: STRETCHFlight ECO neoprene Lining: WARMFLIGHT ECO VELVET thermal lining Seams: Liquide Flex Seal external GBS (glued and blind stitched) seams for maximum flexibility and minimal water entry Entry system: HYDROLOCK Ankle seal system Back ankle pull loop AQUA GLUE eco-friendly lamination 3mm Marathon Sessions - Split Toe Neoprene Surf Booties for Men