Atari Cartridge Sleeve

I like what Atari has been including with their newly released game cartridges and re-releases for the Atari 2600 and 7800, specifically a "sleeve" (made of cardboard) which gives the cartridge a degree of protection from dust and other elements. I have about a hundred of these cartridges all made decades ago, and for the most part, I store them in cardboard or plastic boxes. So additional protection isn't a bad thing.

I searched for 2600/7800 sleeves, and although there are a ton of cartridge holders and whatnot, I couldn't find any actual sleeves. Not saying they're not out there, but my searches came up empty, even though sleeves for other cartridge formats (NES, SNES, GB, Genesis, etc.) are plentiful. Up to now I haven't made any designs worth publishing, but I decided to go for it.

It's a pretty simple design, basically a hollowed, measured cube. The walls have a reasonable thickness and I left it so a standard Atari 2600/7800 cartridge easily slips in and out. If you pref