Gehmann 530PH Rearsight Iris and 1.5X Magnificatiopn w/-4.5 to +4.5 Diopter correction

530PH Iris 1.5X Magnification with -4.5 to +4.5 diopter correction

1.5X Magnification with -4.5 to +4.5 diopter correction
shorter still and adjusts over the wider range 0.5 - 3.0 mm
the fixed seat iris works with individually pin-located tempered spring steel leaves
aim point precisely maintained throughout the wider range of adjustment by introducing a new system of aperture control operated by varying the pressure of a steel tube against the central aim point - guaranteeing a perfect circle
light reflection kept to a minimum by use of matt finishes internally and externally
unique Gehmann patent not found in other irises
Thread Parker Hale
Parker Hale Thread is 7/32“x40Gg BS  (55 degree flankangle)
Redfield use 7/32x40Gg Ansi ( 60 degree flankangle)
If you want to use the iris and polariser alone WITHOUT the diopter you need item #577 which is an adaptor. The adaptor on the diopter is not removeable.