Stepper OnLine makes an entire array of fine motors, drivers, and other CNC products. These closed loop stepper motors are no exception. I own several of these. They are easy to configure, or just leave them as they come out of the box. The advantage of a closed-loop motor is that, with the correct controller, they can sense missed steps and send a fault to the controller to stop the job at hand. The number of missed steps required to trigger a fault condition is programmable within the CL57 driver.
Recommended.