Other gearboxes are those designed for a specific application or industry. They are usually customized or modified versions of standard gearbox models optimized for specific performance requirements, environmental conditions or operating constraints. Other gearboxes are available in a wide variety and can be found in various industries including automotive, aerospace, defense and medical. An example of other gearboxes are planetary gearboxes, which are commonly used in heavy machinery and robotics. Planetary gearboxes use a central sun gear and multiple planet gears that mesh with an outer ring gear, resulting in a compact and efficient design that provides high torque density.