From the full machined precision diopter "TEC-HRO precise-light" 

• All components with high precision from a full milled or turned
• All parts made of steel and aluminum (no plastic!)
• Suspension, precise, backlash-free storage - no "empty clicks" 
• Robust construction - for large caliber and crossbow can be used!
• Exactly reproducible adjustment of elevation confirmed by measuring protocols
• Meeting point shift per click: 1, 2 mm to 50 m, 0.2 mm to 10 m (20 click)
• Glass pearl blasted and anodized surface

The supplied Iris can unscrew and colour filters etc... to be replaced. The existing thread to 9.5 x 1 is compatible with all components available on the market. 

Also lens hoods and so-called "duplex" can be applied.