• neoprene
• Keep fluids cold with the SpeedSok. This neoprene sock fits securely over all of our Speedfil Hydration Systems to provide an easy solution to maintaining cold fluids.
• Simply slide the cover over the entire F1 system and reinsert the drink tube back inside the bottle.
• The A2/F2 Speedsok works with both Speedfil A2 and F2 hydration systems.
• A2/F2 Speedsoks are compatible with any other standard bicycle water bottle.