They remove a relatively large amount of condensate and larger dust particles from the compressed air. Their installation has recently been neglected and the air conditioning process is then less efficient or needed to achieve the same higher cost effect. It is advisable to install them behind the compressor (in front of the air tank, prefilters and Microfilters) so that the amount of condensate (flooding of inserts) does not reduce the efficiency of the filtration system. SA drains are designed so that pressure loss would be as low as possible and air would be constantly passing through all of the internal parts.