I'm just guessing but it's probably in the same genre of anti-tarnish fabric that Lori Grenier sells. Hers is good for something like 25 years and I've used them for a lot of years. Not saying it's the same fabric, but unless they said that something earth-shattering has been developed.... that's what's out there.
They're good btw... I have LG's bent-wood jewelry cabinet and a small jewelry cabinet, all still going great.... 
*~"Never eat more than you can lift......" Miss Piggy~*