Orvis Hydros Spare Spool - Grab a spare spool for your high-performance Hydros reel. A customer favorite for everything from blitzing bonefish runs to small stream trout action, the Hydros uses an innovated design to coil line evenly and put the brakes on hot fish. With spare spools, anglers can carry multiple line options and get more miles from a single reel. Extra Hydros spool for more line options on the water Hydros I for line weights 1-3; 4.7 oz., 3.1in in diameter Hydros II for line weights 3-5; 5 oz., 3.4in in diameter Hydros III for line weights 5-7; 5.5 oz., 3.7in in diameter Hydros IV for line weights 7-9; 6.6 oz., 4in in diameter Hydros V for line weights 9-11; 7.7 oz., 4.25in in diameter