A difficult subject because '37mm' doesn't necessarily mean you want a 37mm filter. I have a couple of Agfa Record III with different lenses but both are 37mm outside diameter, and neither take an exact 37mm filter, there needs to be some wriggle room. So I use Kodak Series 6 filters using a 38mm/1.5" adapter ring, and this is snug secure fit with the tangs of the adapter bent very slightly. The advantage of the Series 6 filters is that there are a lot about on Ebay, and they are a good quality. I don't know if you can get a Kodak Series 6 37mm adapter, but you may find a 38mm is OK as I do.