Polarizer Holder 5PH51 is an original mount with revolving conical angular scale on the face of the holder. This enables the user to set the current position on the scale to any chosen angle independently of the position of the holder. The optical element is secured inside central aperture of the platform of the holder by the threaded retaining ring. The zero on the revolving scale is aligned to the desired axis of transmission. For example rotate the platform to choose the required orientation of polarization. Lock the platform with its fixing screw. Revolve the scale to reset its zero origin. Lock the scale by retightening its own two fixing screws. Now the scale moves simultaneously with the platform of the holder, so you measure angles relative to any initial position. The holder accommodates rotation sensitive optics 1” (25.4 mm) or 2” (50.8 mm) in diameter. The scale is graduated into 2° increments. It is engraved on a conical surface. Angle of the cone is 60°. So the scale is read from a wide angle. The platform rotates the whole 360°. It has a knurled edge for fingers. Also it has 4 holes on its perimeter. Use the same 1.5 mm hex-key to rotate the platform by these holes, to lock the platform, and to lock the revolving conical scale. To mount on posts or bases the holder has M6 and M4 holes in its base. Yet the design is compact. Material: black anodized aluminium. There is shown sample of us of polarizer holder 5PH51 with graduated rotator 5PHH50.