This will help establish the type of a automatic fence gate opener ideal for your gate. A large gate needs a long enough chain and vice versa. How heavy is your gate? Some gate openers are only designed to serve gates of a certain weight. You should establish this before buying a gate opener. You can do it by knowing the weight of the material that your gate is made from. How you plan to power your gate most gates can operate on solar energy, battery backups, and AC power.