The unit you are replacing
The Sepura Sep 60 is a disposable compressed-air oil/water separator. It is not designed to be serviced, so it is replaced as a whole with the STERLING CS75, which is.
Check the label on your unit against the part number above. If it does not match exactly, tell us what it says and we will identify it.
Servicing the CS75
Once fitted, the STERLING CS75 takes replaceable filter bags like any other separator: the CS75SK service kit.