The neoprene spool belts fit snugly over a spinning reel spool are designed to protect your line when the reel is stored and to stop the line from accidentally uncoiling off the spool. These are particularly useful for heavy duty reels that have thick main line or trace where the line clip has difficulty securing it. S Protects line on spool size 1000-2000 M Protects line on spool size 2500-3000 L Protects line on spool size 3500-4500 LL Protects line on spool size 4500-7000