I recently got more SiiD modules to lake xSIID with but they weren’t labelled so I had to test to figure out the colors. Ended up with 3 “testers”, which made for some pretty interesting tidbits.
The advantage here is the LED is so far away from the coil you should have no problem with your phone covering it. They are 7mm by 40mm though. Long.
Considering what to do with them… might put up for sale as “odds and ends”… might implant them… dunno, but I find it interesting.