I will take a step sideways.
I have a few coins in air-tights, but they are somewhat different:
I use ex British Royal Mint screw seal acrylic capsules that were originally used for their individual proof coins
These capsules come is a range of sizes. Since they are recycled, originally for individual proof issues or broken proof sets, I buy them very cheaply from my LCS. The screw seal is very positive, and very secure.
I have a few coins in air-tights, but they are somewhat different:
I use ex British Royal Mint screw seal acrylic capsules that were originally used for their individual proof coins
These capsules come is a range of sizes. Since they are recycled, originally for individual proof issues or broken proof sets, I buy them very cheaply from my LCS. The screw seal is very positive, and very secure.