These are an upgrade to stock Penn reel seats that fit a number of models. They are manufactured from aluminum in three sizes. The sizes and reels they fit are as follows;
 
#30-49 (Narrow base) models: 100, 110, 180, 190, 146, 49, 249, 501, 506, Monofil 27.
 
#30-66 (Mid witdth base) models: 65, 66, 99(JigMaster), 112H, 145, 150, 160, 165, 209, 210, 309, Monofil 26.
 
#30-200 (Wide base) models: 49A, 140, 155,  200, 25, 250, 259, 350, 500, 500S, 505, 67, Monofil 25
 
#30-2.75 (Extra Wide), Kit comes with a base and 2 crossbars.
(please note) Crossbars can be purchased separately here.