Differing in outside diameters and overall lengths, the two variants offer torque capacities from 12Nm to 450Nm and 850Nm respectively, and in six and seven sizes and three ratios of 50, 100 and 160:1. The space-saving design includes a hollow shaft that allows cables, pipes and other services to be passed through the centre of the unit. With a high level of positioning accuracy, the robots can be used in any high precision application, not limited to robotic or semiconductor applications.