An extremely thin profile filter is sized and configured to be installed between tubing couplers of an automotive air conditioning system in regions of an engine compartment that are cramped or otherwise will not accommodate a longer in-line filter. The filter includes a thin flat filter housing formed from first and second thin shells joined together at opposed inside faces. Each shell is formed with a shallow well on its inside face and the wells align to define an interior camber within the filter housing. The outside opposing faces of the filter housing are configured to mate with corresponding sections of a tubing coupler so that the filter is installed by being sandwiched between the sections of the tubing coupler.