Severn Engineering Permeability Indicator #5034

Got this vintage Severn Engineering permeability indicator. It's a pretty cool piece of niche engineering history from Annapolis. Comes in the original wooden box with four different reference standards (1.2, 1.6, 2.0, and 2.5). Everything looks to be in decent shape for its age, though I havent tested it for calibration or anything like that. Great for a collector of old scientific instruments or someone who actually needs to check magnetic permeability on the fly. Box has some minor wear but still latches fine.