Yes it's a shopping app on iPhone. I was first introduced to them when
Mansur Gavriel bags were all the rage and impossible to find back in the day... I think they are only available on Apple devices? You download it from the app store and send in a request of whatever you're looking for, and they will check with their networks (designers, major department stores, boutiques, buyers etc.) to see what they can find. It's worth it if you know what you want and don't mind paying full price or even a little extra (with the service added) for it.