Hastings Triplet Magnifier 10X
Unique three-element design provides the ultimate in distortion free, color-correct viewing, facilitating reduction or elimination of "pin cushion" distortion and chromatic and spherical aberrations. Two concave meniscus elements are cemented to a double convex lens, then mounted with threaded retaining rings in a machined black anodized metal cell which swing into a protective case. The case doubles as a handle for viewing.
We caution buyers that laws of physics dictate that both the diameter and working distance of a magnifier must decline as power increases. Accordingly, the 10X system, while an excellent high-power magnifier, is relatively small and has a short working distance. The next step from the 10X Hastings is a full microscope.
More information: https://www.scientificsonline.com/product/edmund-scientifics-10x-hastings-triplet