This shallow SV spool is to improve casting performance of Daiwa Alpahs SV 800 reels. Flat bottom, ultra light-weight 12g spool to improve casting performance especially for ultra light weight rigs 3g-7g 1/8-1/4oz. Casts great for heavier than 3g 1/8oz. 0.285mm(US10lb)-55m(60yds)