This Martin hub is one of two simplex sprockets used in a roller chain coupler for joining and transmitting power to two perpendicular shafts. It is made of sintered steel for strength and hardness and has hardened teeth for resistance to wear and fatigue. When connected, the coupler accommodates for up to 2 degrees of angular misalignment between shafts, and is used in low-speed, high-torque applications. It has a keyway for preventing rotation between the two elements. This sprocket meets American National Standard Institute (ANSI) standards, and is suitable for use in farming, mining, metal manufacturing, among other applications.

Roller chain sprockets are circular gear elements with deep, uniformly spaced teeth ringing the circumference of the gear. The distance from the peak of one tooth to the next is called the pitch, and is commonly measured in 1/8" increments. In the center of the sprocket is the bore (hole) which, depending on the sprocket's design and application, might be augmented by a bushing or a bearing through which it is fixed to a shaft. The sprocket transfers power and motion by a roller chain that is threaded over the teeth of the sprocket. The chain links align with the sprocket's pitch and at a length that prevents the chain from skipping, slipping, or binding. Mounting space varies in application and generally determines the type of hub—a protruding, raised lip encircling the bore—a sprocket has. A hub on either side of the sprocket is a Type C hub, a hub on one side of the sprocket is a Type B hub, and a no hub on either side is a Type A hub. Some applications may require a sprocket to be swapped onto a shaft of a different diameter. To make this swapping easier, designs have evolved where a sprocket might have a bore of a particular uniform size, and then bushings that have an outside diameter matching the bore of the sprocket but have varying inside bore diameters to accommodate different sized shafts can be swapped in as needed. Roller chain sprockets are used in a broad range of applications where the drive power of an engine needs to be transferred into motion, such as in motor vehicles, conveyors, escalators, agricultural, forestry and mining equipment, aeronautics, robotics and space exploration, among others.

Martin Sprocket & Gear manufactures power transmission products, material handling components, and industrial hand tools. The company, founded in 1951 and headquartered in Arlington, TX, meets International Organization for Standardization (ISO) standard 9001:2008.