I'm using this one, its the long arm version, pretty solid.
I Will post some pics later of my installation
The RAM-B-107U-C consists of a LONG double socket arm, 2.5" diameter round base with the universal AMPS hole pattern and connecting Humminbird/Apelco marine adapter base. Designed into the mount is a 1" diameter patented rubber ball and socket system with adjustment points at both socket ends of the arm. Rubber ball and socket technology allows for almost infinite adjustment and perfect viewing angles.