Sourcing T5577 chips for custom wearables

For what it’s worth, I have a 25MM T5577 stuck with 3M behind my Pebble 2 watch emulating HID Prox, I found if I place the SIDE of the watch against the SIDE of the reader, it will work just fine, but this will obviously depend on the reader and how it was installed – can’t do this if it’s flush mounted.