This precision grating was made for Jerrell-Ash by Bausch & Lomb. Much of the following information was taken from the nomenclature label fixed to the back of the grating holder.

Grating size - 60 x 60 mm
Focal length - infinity
Grooves / mm - 147.5
Blazed at 300nm
Part number 11-074
Catalog number 985-30-48-18
Coating - Al (?)

The grating is in excellent condition. There are a very few tiny marks on the grating, but the coating is excellent. The grating includes the Jerrel-Ash holder shown in the photos.

Photo set 1649