Indoor cats are less interesting. I'd see food bowl, water fountain, litter box, bed, couch, maybe a view out the window now and then.
Proud owner of an Aeronaut (indigo), Med. Cafe (steel, indigo), mini organizer (blue), med. organizer (cork), larger organizer (cork). Always thinking about what to get next.
He has a GPS tracker in the works.
Very useful for indoor/outdoor cats, I don't recommend it but sometimes it is the only way to give a former feral a decent life.
And great for all dogs, if I were a dog owner, I would buy one in a minute.
Most microchips are not readable by all readers, companies making the microchips are still not working together to make an universal reader.
I would love to see all beloved pouches fitted with gps trackers. It would make it much easier for them to be found and less likely to end up lost forever.