This designation basically describes the spool capacity of each reel.
On the 40 you may use 270 yards of 8 Lbs, 190 yards of 10 lb or 70+ yards of 12 lb capacity line. I use braided line and was able to spool 125 yards of 30 lb Spiderwire Stealth Braid without any problem.
The 55 has a bigger spool with more capacity and the 30 less.
answered 3 weeks, 2 days ago
Reel size options should be match to the size of pole you are going use it on . A 6.5' pole to a 30 , 7.5' pole to 40 , 8.6'pole to a 55
Size of the reel itself. I have the smallest which is the 30. It holds 6 lb/200 yds, 8 lbs/ 160 yds, 10lbs/110 yds. You can look the specifics about each reel up on okuma's website as far as each size goes.