Portarod offers Offshore Single Rod Holders so that you may add additional holders to your system. The Single is 19″ in length with a 1.77″ ID and a 1.476″ clamp. it is made of aluminum with Vinyl end caps with the top one notched.
Fishing Rod Holder for Offshore System
Inner Diameter: 1.77″
Aluminum with Black Vinyl End Caps (top one is notched)