Technical features:
* Item :300S, 300R, 300L, 300XL
* Power: 3.0X
* Working distance: 340mm(S),420mm(R),500mm(L),550mm(XL)
* Depth of view: 60mm (S); 80mm (R); 90mm (L); 100mm(XL)
* Field of View: 60mm (S); 80mm (R); 90mm (L); 100mm(XL)
* Weight: 48g
* Frames: Ni-alloy or Titanium