Barographs?

A word of caution. Go with someone who has a known reputation for
calibrating baragraphs used for soaring badges.

I sent mine to a company that was very responsive and provided a quick
turn-around. However, the calibration documentation was not accepted
when I submitted it with my flight. The beginning and ending altitude
(sea-level) was not labeled next to the bottom "steps" on the lab
trace. So, if you don't use someone like Joe Trinkwalder, you might
think about asking Judy to verify the calibration before bothering to
use it. She will reject on the slightest technicality. Although that's
no fault of hers. She's just going by the book.