The purpose of air dryers is to suppress the dew point of your compressed air by removing water from it. Compressed air can contain moisture, which, under the right conditions, can reach the dew point temperature and condense into a harmful liquid.
The Words Warthog and the Stylized Warthog are Registered in U.S. Patent and Trademark Office. Reg. No. 7,109,357 and 7,109,356