https://www.jpscorner.com/collections/model-x6d-air-tite-coin-holders-with-black-rings/products/ring-type-air-tite-model-x6d-39mm-black-1

JPs Corner is a good source. Their prices vary from $1.10 to 55¢ per capsule depending on quantity purchased. $1.10ea for 1, 55.1¢ea if you buy 10,000. lol

I happen to have 96 of them (75 black ring, 21 white ring) that you can have for $50 plus actual shipping whatever that may be.
Please let me know if you are interested.

Best Regards,
Murph