Did u get it from VA? If you bought ur set from VA i guess we own the same compressor lah! Well the uncle there said the same thing to me about the moisture trap thingy. I was a little doubtful about that as well. Since the compressor does not has a moisture trap in it, all the compressed water goes into the tank and later if you open the valve at the bottom of the tank, you will see water coming out.

I was freaked out by this because i thought that this will eventually rust the tank inside out so to be safe, i bought a moisture trap and install it myself. The moisture trap is around rm65++ if i am not mistaken.