I know I had 2 Panerai cloths but I lost one of them somehow. I think I got it in a Panerai goodie bag from either the Panerai Boutique, from SIHH, or from an official Panerai dinner event. I do know many brands give them away cause I had a white IWC microfiber cloth (lost that one too
) and Richard Mille has one the same size as well. If you have a good relationship with an authorized dealer, I'm sure your AD can give u one for free cause they should get promotional items, such as these microfiber cloths, in every so often.
Cheers,
Anthony