For WRS series stage, the rotating top surface is plane with mounting holes as is evident from the photograph. This rotation stage provides fine movement throughout 360 degree. Coarse movement is not available in WRSC series. Drive mechanism used in this case is a worm gear assembly precisely matched to minimize play and back-lash. Radial play is eliminated by the use of preloaded thrust bearing using balls as rolling elements. Graduated rotating top is provided with tapped holes for component mounting. Movement is achieved by a graduated rotating knob connected to the worm of the drive assembly. Standard stages are constructed in aluminium alloy and finished by black anodizing.