Technical features:
* Item : 400KS, 400KR, 400KL, 400KXL
* Power: 4.0X
* Working distance: 340mm(S),420mm(R),500mm(L),550mm(XL)
* Depth of view: 40mm (S); 40mm (R); 40mm (L); 40mm(XL)
* Field of View: 50mm (S); 55mm (R); 60mm (L); 70mm(XL)
* Weight: 80g
* Frames: Ni-alloy or Titanium