Draught excluder routed into door frame

I've spotted a draught excluder that was routed into the door frame, so that the door closes against the stop as normal, but is seal around the perimeter of the door.

Similar to a Intumescent Strip, but the seal was a thin strip of rubber that was angled, so the door slides past it, creating the seal.

Now, where can I get some of these?

I'm trying to draught proof a door and thought that these were brilliant. i'm sure I spotted them in a new build flat.
I don't like a door with sticky on draught proofing bits. It makes the door look terrible and unprofessional.

Also, I'm trying to seal the bottom of the door, but it's wood between both rooms, but one room is sloped, so there is a large gap below the door when closed. I used to have a spring type excluder, but the spring just broke, but can't find these anywhere either!!

ironmongery direct will have all the stuff you're looking for if you can't find it in your local merchants.

Normally, in the merchants next to the door frames, is a basket or rack with these

In some cases, these can bind on the doors, and you may need to plane the door more than normal. And then as the rubber wears (or the door shrinks) ...... you get a draughts!