It was to allow a small animal (cat) into a room, but not a large animal. A plastic 2 piece device that kind of fit on the door knob. I have googled and binged and yahooed but I cannot find. I know I saw the recommendation here, but can’t even remember what the thread was called.
Anyone? I broke mine the other day, and it keeps the cats from flinging open the bedroom door when they need to get their skinny selves in or out the bedroom.
That was from me, I think. And I can’t remember what it’s called either, but let me go look…
LatchNVent!
One of my favorite products 
eta:
Ruh-ro, there may be a problem… (from their FB page)
Thank you SO much!!!
You’re welcome.
I love it when I can actually make a useful contribution here! 
Wasn’t there another thread here just a week or two ago, suggesting that even a solidly closed door won’t keep a cat out? So just do that.
I have double bifold doors. So if partially opened the profile is a “W” shape. One of the cats flings his body at it until he can get it open. It’s like something out a horror movie, with all the banging and a claw grasping around the gap. A bungee cord can delay him long enough to make him bored but not keep him out if he wishes to squeeze. But that makes the door difficult to open from the other side. Any ideas? I put a (weak) magnet latch in and it affected him for about… 2 days.
I just put a sandal in the doorway to keep the door from closing completely, and a small pile of dirty clothes (yes, I’m male and proud of it) to apply pressure to keep the door closed - the fabric pushes with about a half pound of pressure - kitty can slip through and the weight pushes the door back up to the sandal.
No shipping required.
A hinge-pin type door opener may work as well, but the molding in this place is too flimsy too use them.
The purpose is to let the cat use the litter but not to allow the dog access to eat it! The dog could prob push past the laundry. I love my latch n vent…now I need something to keep the dog from eating the cat’s food. It kind of freaks people out to see the cat jump up on the kitchen table to eat. I’m not as squicked out about germs as most people.
Looks like you solved it, but what kind of dog? I got a large sterilite to keep the smallish dog out. One cat doesn’t like lidded boxes so that was out.
I’d like to see those people try to keep cats off.
For our dog, we just used a baby gate to keep her out of the laundry room where we had the litter box.
The nice thing about these gadgets is that the door works like a normal door. No stepping over baby gates or undoing hooks or bungees or moving piles of stuff. Just turn the knob and go and swing it closed when behind you.
For thelurkinghorror’s cat and the bifold doors, have you tried the Ssscat deterrant system? Video here of how it works. The refills are expensive, but I’ve found that Office Depot’s canned air works just as well (or any kind that you can get the spray nozzle off easily). Not quite as much power to the spray, but they still don’t like it!