Air Water Separator

Are air water separators (such as Tuxing) necessary / suggested for filling directly to PCP airguns when using a Yong Heng compressor or are the separators meant for scuba? If they are necessary or suggested, are there any other brands? I'm a newbie to PCP and compressors, and at beginning of learning curve. Thank you.
 
I have had the Tuxing filter installed after my tiny YH filter for over a year now and it is still good although it has picked up a slight amount of moisture. Most of the water can be removed simply by remembering to purge the system while filling every <5 minutes and changing out the YH cigarette filter every twenty. You can set the old filter out to dry and reuse it several times. So unless you live in a very humid area >60% I would guess that you would for the most part be OK without the Tuxing. Although for me a little extra never hurts.