thickest outer record sleeves, where to buy them?

3 or 4 years ago I bought a very thick outer plastic sleeves for my records. They can stand upright without a record inside and they are 100% crystal clear transparent. Im trying to find those same sleeves in the market but I can't... can you help me please? thanks in advance
I got 5.0 ml ones, and I actually don't like them. They are a harder, stiffer plastic. So much so, that they are a pain to work with. They would be cool to display an album, because they look very clear, but were not practical from a convenience factor. The ones I have are exactly what you describe, they can STAND UPRIGHT on their own. I will double check, but I am near positive I got them at SLEEVE CITY. If you can't get them, I will sell you mine for what I paid for them. Just curious, why do you like these?