These are the same high-quality inner sleeves that Mobile Fidelity uses for their vinyl releases. They are imported, three-ply, anti-static, premium sleeves (similar to rice paper) and work with both LPs and laser discs. Back construction consists of a paper layer sandwiched between two sheets of high-density polyethylene (HDPE) with a translucent HDPE front.
These are the best sleeves out there, and even though they might be easily available in other locations, I found that this was the store with the best price ( $5.00 cheaper than the closest price). I buy them all from this store.