The NIKRFK focus drive with an integral electronic clutch is now available from Prior Scientific Inc. Designed for the Nikon Ti, 80i and FN1 microscopes, the focus drive offers resolution and repeatability under software control. The electronic clutch can be disengaged with the push of a button to offer users smooth operation when using the microscope’s manual focus knob. An optional focus encoder kit provides accuracy with a 50-nm-resolution probe style encoder. The kit includes a controller, a focus drive mechanism, cables and a power supply. Available push-button functions on the device include engage and disengage clutches, go to zero, set zero, change speed, and buttons to move up or down. The drive delivers repeatability of 100 nm with an encoder, features a resolution programmable to 10 nm and operates at a speed of 320 µm/s.