3.680 MHz Quartz Crystal Resonator HC49/U Low Profile case, Amateur Radio 80m band,
 
ACT Branded.
 
All modes - Telephony, Telegraphy    
          3,663 kHz may be used for UK emergency comms traffic.    
          3,690 kHz SSB QRP (low power) Centre of Activity.
 
I have received strong OFFENBACH METO signals usinf this crystal in a 'pixie' Rx.  Fed the signal into 'fldigi' and received the decoded weather information.