【 rules   G: 4X20 with a cross.
[magnification] : 4 times.
[objective lens diameter] : 20mm.
The tube   Diameter: 19 mm
The whole   Length: about 270mm.
Exit pupil distance: 70-85mm.
【 material   Quality: plastic steel
【 mirror   Film: 100% optical glass.
[focal length adjustment] : feasible.
[alignment adjustment] : feasible (up and down, left and right buttons can be adjusted)
[product content] : one set of mirror, one copy of instruction, one set of protective mirror, color box. The support is fixed on the mirror body.