Usually,there is number of 10X42, 12X42,or 12X50, 40X60, even 80X100 for our JAXY monocular.Which show its magnification and dia. of objective lens in mm.
However,for some certain monocular---cheap ranges,40X60,80X100 is likely false for advertising purpose,which can be printed as order request,which is used to be and accepted in the field of optics.
The real magnification usually go 8X, or 10X or 12X, the lens diameter:42mm.Which making it a balance between magnification and image quality.
Acutally,we do have high magnification of 25X,30X,40X of binoculars or monoculars in our JAXY optics, and big eye lens 82mm, 100mm etc.
such as,JAXY coin operation binoculars 25X100, 40X100,30X120. Those giant binoculars are super nice and not cheap either.