Neo-Geo rental unit?

In the couple US Neo games that I just got in the back of the instructions it says for use in the Neo Geo rental system. But in the Japanese instructions it says for use in the Neo Geo system.
That confuses me a bit, ever since I can remember the Neo Geo was a very expensive system you could buy in the US. I don't remember it being a rental only system before that. But I'm not sure. Anyone know?

MVS games with SNK-G on them were rented out to arcade ops.

I'm sorry I guess I was not specific. It's AES.

Search function for "rental" brings up http://www.neo-geo.com/forums/showthread.php?t=111487&highlight=rental

this kind of thing was discussed a few days ago.

Wow that's crazy that I missed it since I've been an active member again for a couple weeks.