This bobbin holder is ideal for tying saltwater flies.With the gravity system included, the 29g weight ensures that the thread tension is maintained.By tightening the screws on both sides of the gravity system, it is possible to tie with stronger pressure.This bobbin holder has a unique design with a short protrusion that prevents the ceramic tube from being damaged by strong pressure.Uses high-quality ceramic (zirconia) tube to prevent thread breakage.Gravity system is standard equipment that increases the weight and adjusts the thread tension.One dedicated bobbin threader is included..