As far as your concern, and upto my knowledge, there is no RF parts in this design.
This circuit seems to be a cheap Chinese design, which uses...
1. COB IC (Big black round dot) - for processing.
2. A crystal oscillator (silver cylinder), to provide a clock frequency to COB IC.
3. some kind of sensor (Leaded part on bottom left.)
4. a Switch Input (PCB traces near C/F print) - (C/F seems to be Celsius / Fahrenheit)
5. Few passive component. - to make circuit work.
6. Red / Black wires for battery connection.