Whitey says: The New PR Bobbin from Shimano is strong, lightweight and simple device that is able to achieve stunning PR knots and binds with ease. It comes with a built in line tensioner as well as double O-rings to lock in your braid, preventing slippage during your winding. It also features a hard zirconium ring at the tip that reduces heat and friction by allowing the braid to run smoother under tension. Suits Line PE1.5 - 8