RFID Guardian. Having over 13 years of experience in RFID and NFC, I am fully aware of the dangers and ease of reading from a "tap and swipe" credit card. My product (which I am willing to dropship with blank labels and/or your brand name for an additional cost) is the Guardian Card.
It is a signal jammer* that will block attempts at reading your cards without your permission. Rather than individual sleeves for every card or the ugly metal wallets that are currently the only solution on the market, my patent protected device is made of a durable plastic and is the size of just about 2.5 credit cards in thickness.
You can watch a video of it blocking a reading attempt outside of a wallet or inside of a wallet. You can also purchase lots of 1000 on eBay or any size order from 1000+ on AliBaba. Or you can always just contact me directly here!
We manufacture our product here in the US for orders of up to 150,000. Larger orders will often require us to use one of our manufacturing partners in Vietnam or China (contacts we have built through our involvement in RFID through ActiveWave). My ultimate goal is to open a factory here, and we're getting closer to that every day!
If you mention this post, I will see what I can do about a discount on your order, putting your brand on the cards for free, or something else special, depending on the size of your order.
*Note: It does not actually jam signals in the technical sense, as the FCC does not allow that, but rather, reflects and readjusts the frequency of a reader. I am using the phrase jammer as my market research has shown it to be the colloquially used term to describe what my product does.