Vintage mason jar zinc caps, three total.  These are marked Atlas/Boyds.  Atlas is marked on the Zinc cap, and Boyds is embossed on the glass inside the cap. 

The caps have corrosion, which is pretty common for old used caps, but the glass in intact. 

I will be listing hundreds of antiques, vintage books, magazines and media in the coming weeks and months. Keep a look out for additional listings, and thanks for supporting this cancer survivor and small business!