The Cressi Float Line is available in 4 different lengths. Depending on how deep you are intending to dive will determine which rope length you should purchase. The float rope is designed to attach your speargun to your float so you can tow the float along whenever you go, letting boats know that you are in the water. It also prevents a shot fish from swimming off with your gun as it will always be attached to the floating buoy if you accidentally drop your gun.