Single Lens(BLACK)
Single Lens(SILVER)
Double Lens(S)
Double Lens(L)
Single Lens(With Needle)
Difference between single and double lens type
In comparison with single lens type, the distortion variability around the lens is less in the double lens type. When your eye is close to the lens the variability is small. However, as the distance increases between the lens and your eyes, the variability increases.