Need help identifying part, possibly a resonator

[Elyse Dereux]

I have parts that I need to identify. As you would see below, they all have a manufacturer marking of a large C, with a small o or c inside of it... 1.jpg came from a radio receiver with marking 2.00S or perhaps 2.003. At 2.jpg, which came from a transmitter have a marking 4.00Z. And, lastly 3.jpg also came from a transmitter, with a 4.00h.

Can you guys help me out?

 

[shrtrnd]

May not be much help, but muRata Ceralock ceramic resonators have the Large 'C' with a small 'm' inside of it as their logo. Might that be an 'm' ?
They DO look like resonators to me.

 

[Arouse1973]

Yes look like 2 MHz and 4MHz resonators. The ones with 3 pins don't need external capacitors.
Adam