A chain driven operator has a chain that attaches to both ends of the gate using a bracket, it runs the full length of the gate and extended at the rear, is feed through 2 idlers and a power driven gear. It is a lot easier to install than Rack and Pinion. Steel Rack and pinion gate openers is the norm in Europe and the chain gate opener are the norm in the US. The Metal Steel rack sections which are 39" long each get bolted to the bottom part of the gate it must be straight in order to function properly, the rack sticks out about an inch off the side of your gate across the length of the gate. On the bottom of this bar there are teeth that face downward, these teeth interact with a mechanized Steel gear on the opener that moves the gate back and forth, that is how is name Rack and Pinion . The advantage of Steel rack and pinion is that once it is installed it is quiet, highly reliable, and requires little to no maintenance, it is much harder to install and you might even have to make modification on the gate 3 feet 3 inches in length in each section of nylon covered steel gear rack for sliding gate motors. There are 6 fixing points on each section length with proper slots and protruding lip to slide securely in to the slot on the next section of rack. Comes complete with 6 washers and fixing screws ( Hardware ). Can be used on Residential as well as Commercial gates. The solid steel inner core is made of 10 mm solid bar. Will fit most brand of gate openers like: Lockmaster, BFT, FAAC, Viper, Victory, Alenko, TAU, SEA.