50 Micron pinhole for foucault tester or other scientific purposes. Small 1/2 inch holder. 
This pinhole is precision laserdrilled then mounted into an aluminum holder is 0.6mm thick and the pinhole is 0.05mm or only .002 of an inch thick. These pinholes are outstanding and unrivaled quality due to the thinness of the pinhole and the perfect forming of the aperture using the most advanced methods.
Holders can be custom machined to and size that suits your needs