The very compact ZWO Helical Focuser allows for precise focusing of eyepices or cameras. It is ideal in conection with an off-axis-guider and a guide-camera. The focuser features a female T2-thread on the telescope side, while allowing the attachement of 1.25" equipment on the eyepice/camera side. In addition, there is a male T2 thread on the camera side. During focusing, the attached accessories keep their orientation and don't rotate. The exact focus position can be fixed with a clamp screw.