The Ram system consists of a ball mounted to your vehicle and another one mounted on what you want to hold with an arm in between. If you think of the ball and arm like your shoulder and arm being a ball and socket with an arm on the socket you have the basic idea of the Ram system. The photos below show a Ram-B-236 ball that can screw into a riser plate, stem nut etc. You can also use a U bolt or clutch mount with ball on this end. Next in line is the arm, they come in 3 lengths, regular, long and extra long. The regular length one is shown and my recommendation for most applications. Next is a the Ram-B-238 diamond shaped mounting plate. It mounts to, in this case a GPS cradle to hold a Garmin GPS. The cradle could also be a Ipod holder, radar detector holder, sat radio holder etc. In the case of a drink holder. the drink holder comes with it's own ball.
We have made it easy for you to order by putting the 3 parts less the Ram-B-236 ball in one convenience package when you order. You have a choice on arm length.
The balls shown are a hard rubber 1inch in diameter. If you have a Garmin and it has a ball socket on the back it IS NOT the same size as the Ram system and you can't snap a Ram ball into it