On Tuesday, September 20, 2016 at 5:26:01 PM UTC-7, Michael Terrell wrote:
I finally found a stereo microscope that I could afford. It is a B&L
StereoZoom4 on a boom. I need a pair of 23mm 10X eyepieces, and the 38
mm light mounting ring.

Sweet!
I've enjoyed the StereoZoom 3 (but never found a boom unattached
to a large pricetag). Wide field eyepieces are a must, I've been happy with these

http://www.surplusshed.com/pages/item/l1861d.html

but if you can find the 5x ones, get them instead.
Glancing illumination is sometimes better than the light ring, consider one of these

http://www.ikea.com/us/en/catalog/products/20169658/