Choosing which Duplex Insert is right for you:
There are two main indicators for the diameter of the ring :
- Distance Eye to Iris-Aperture And Length of Lenshood II That’s all you need.
- If you have Rear-sight Spy, you will need a diameter between 3,8 and 4,2 with a distance eye to Iris aperture of 4 cm to 5 cm
- Feinwerkbau rear-sight, you need a long Lenshood II, there are 4,3 – 4,8
- Anschütz 7000er rear-sight also with long lenshood II it´s similar to Feinwerkbau.
Length of sightline or Diameter of front-sight tunnel, doers not matter.