The Scotty Extended Rodmaster II No.346 comes with the rod holder, the height extender, and the round flush deck mount.
Dimensions: 3 3/4" diameter
Bolting Dimensions: 2 3/16" X 2 3/16"
WARNING: This product can expose you to chemicals including Di(2-ethylhexyl)phthalate (DHEP) and lead, which are known to the State of California to cause cancer, and birth defects or other reproductive harm. For more information, go to www.P65Warnings.ca.gov