The Sub Gravity FSI (Free-Spinning Insert) is available in 3 sizes to perfectly match up with your favorite Sub Gravity Spool just order the same “size” as your Sub Gravity Spool
22mm (15m Spool)
32mm (30m Spool)
42mm (45m Spool)
The FSI is a spool insert that provides a low friction, free-spinning center section on the Sub Gravity RES Spool.
