It, probably along with the two capacitors, C8 and C9, that can be seen in that picture, will be used to form an accurate and stable 4MHz signal for the circuit it is connected to. This might typically be a microcontroller.Can please explain to me its main function.
Pretty sure its ceramic - I've never seen a quartz in that package style.It is a 4MHz ceramic resonator or, possibly a 4MHz quartz crystal.
Murata is a manufacturer that springs to mind - there's usually a collection of example circuits at the back of their catalogue.Can please explain to me its main function.