Gehmann - Rear Iris Default:Twin Polariser (551) you need the mounting rings

you need the mounting rings to fit this diameter

Fitted with elastic for a comfortable but flexible fit

AHG9736     M18 - 2

Search the link above to find the correct box for your rounds

1 MIL (10mm)

Gehmann - Rear Iris Default:Twin Polariser (551) you need the mounting rings(#PH510) Gehmann Rear Iris Adjustment range 0. 5mm 3. 0mm. Thread size suits Parker Hale or Redfield. (#550) Gehmann Rear Iris twin polariser, Adjustment range 0. 5mm 3. 0mm. Thread size 9. 5mm. (#551) Gehmann rearsight iris with twin polarisers and 1. 5x diopter, incorporates #550. Adjustment range 0. 5 3. 0mm. Thread size 9. 5mm (#566) Incorporates the patented 510 iris, Adjustable over a wider range of 0. 5 3. 0mm. Filters are of the highest