I have 3 12' OceanMasters. One with a Penn 3/0, one with a Daiwa 50HSD, and one with an Okuma convector. I would have no problem with a 4/0 or 4/0 wide and I am gonna try a 6/0wide on them. Gundoc is right about the brass spools. I had a 6/0 with a brass spool Igot rid of cause it casted like ****. I used to have a Daiwa 400H that casted every bit as good as my 50HSD. There a many, many choices out there. The 555GS that GD mentioned is also an awesome reel.