Help identify crystal filter

[MarkAren]

Hi,

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