The AD/ADR Series of planetary gearboxes from Apex Dynamics Inc., a Taiwanese company (apexdyna.com), is for continuous or cyclic duty in high-speed, high-precision applications. They generate between 14 and 2,000 Nm of torque, and backlash is 5 arc-min or less on one-stage models and 7 arc-min or less on two-stage models. They are completely sealed and can be installed in any orientation. The ADR is a right-angle version with a spiral-bevel gear on the input side. Its short, rigid housing is compatible with most any standard motor.