Cressi sarago These socks for fins with strap or foot pocket are made of soft highly elastic nylonlined neoprene 3 mm. They prevent heat loss and keep feet warm. The smooth skin neoprene on the ankle allows maximum adherence between the sock and the leg of the wetsuit, reducing the passage of water. The sole is entirely non-slip. The construction of the blind stitch seam further improves comfort and aesthetics.