The focal length of a magnifying glass is fixed and cannot be mechanically changed, but by adjusting the object distance (the distance between the magnifying glass and the object), a clear image can be obtained.

1.8X, the observation object distance is 3-6cm, and the optimal observation object distance is 5cm.

2. 15X, the observation object distance is 2-6cm, and the optimal observation object distance is 2-3cm.

3.23X, the observation object distance is 1-6cm, and the optimal observation object distance is 1-2cm.

Operation steps:

Wear the magnifying glass to your eyes.

Keep the object still, and move it back and forth slowly until the image is clearest.

Attention: If the magnifying glass is too far away from the object during movement (beyond the observation distance), an inverted real image will be formed, and even the image cannot be seen clearly. This does not meet the requirements of magnification observation and cannot be magnified.

Features:
Double polished and crystal clear acrylic lens with 3 magnification options, no distortion but high clarity.
High-brightness LED lights with adjustable dimmable switch, flexible to adjust desired lighting brightness for a better viewing effect.
Suitable for examining and reading fine print in newspapers, documents, maps, coins, stamps, electronic parts, jewelry, photos, and pill bottles, or for repair work on watches, clocks, mobile phones, etc.
Ideal gift for seniors, hobbyists, and professionals, providing thoughtful helpful assistance for vision impairment.

Specifications
Material: ABS + Acrylic lens
Color: White
Lens Magnification: 8x, 15x, 23x (Use 2 lenses at the same time)
Lens Focal Length: 62mm, 33mm, 21mm
Battery: 6* LR1130 (Batteries included)
Lighting Source: 2 * LED Light
Unfolded Size: 175 * 155 * 55 mm
Folded Size: 85* 155* 55mm

Package Included:
1* Magnifier
1* User Manual

This product has three magnifications, but only two lenses. The other magnification is the sum of the lenses.