This item is used on multiple models.
Sometimes there is too much play on the main gear handle shaft which can result in the gears grinding. Some reels don't need a shim, others may need 1 to 3, it varies by each individual reel.
The shim for this main gear is:
8A-5000SG on these reels: BTLII5000, BTLII6000, CFT5000, CFT6000, FRC5000, FRC6000, FRCII5000, FRCII6000, SG5000, SG6000
8A-7000PUR on these reels: BTL5000, BTL6000