There is a high demand for these because of their low price.
Stocks are limited.
The design is similar to the folded optics of the original McArthur style field microscope. Servicing requires stripping down of the microscope and checking optics are secure and clean and is well within the capabilities of anyone with minimal skills and equipment. For the price they offer a performance that is more than acceptable for simple field work or indoors work where a more advanced microscope and optics isn't available. Brian suggests people buy two to ensure one good one as there is some variability in quality. Onview.net therefore provide 1 pair of microscopes on each order.