A gear coupling is a type of mechanical device used to connect two rotating shafts together in order to transmit power. The coupling is made up of two or more gears that are connected together by a series of connecting rods. The gears are usually meshed together so that they rotate in the same direction, allowing for smooth power transmission between the shafts. Gear couplings are used in a wide range of applications, from automotive and industrial machinery to marine and aerospace. They are highly reliable, efficient, and cost-effective compared to other types of couplings.