Help identify Xtal filter

Hi,

I hope that this isn’t too far of topic…

I have some crystal filters that I am hoping someone can help me identify.

21.4MHz, possibly 6 pole, made from 3 x 3 pin HC-49u cans, appears to be about 15kHz wide at -3dB

Marking is 03047A

Any help with a data sheet or termination impedance will be most welcome.

Thanks, Mark