Rev A
Serial below 20000, dongle-style USB receiver.
This is Pattern 2: a chooser parent plus revision-specific child pages. Use it when revisions diverge substantially. The parent carries the search identity (“wireless pendant”) and asks the identifying question so readers — and bots — land on the right variant instead of an orphaned duplicate.
Check the sticker on the back of the pendant for the serial number.
Rev A
Serial below 20000, dongle-style USB receiver.
Rev B
Serial 20000 or higher, integrated antenna receiver.