commonly used as a threaded u201c unloader port u201d for connection of an electrical pressure switch for example operable to release air trapped between the compressor and the valve subsequent to the compressor shutting off in order to facilitate proper re start of the compressor the valve 10 of the present invention is compact in size and has a small number of component parts to minimize cost the valve is reliable in operation in the severe environment typical for a compressor discharge at the open position the valve provides good internal flow characteristics with generally restriction free flow areas minimal turning i e the flow proceeds generally straight through the valve and with the only obstructions being the three arms 50 therefore the valve avoids producing a substantial decrease in pressure as air flows through the valve assembly of the valve 10 is facilitated by the convenient position of the retainer 16 at the exit end 32 and its attachment by crimping the end in view of the above it will be seen that the several objects of the invention are achieved and other advantageous results obtained when introducing elements of the present invention or the preferred embodiment s thereof the articles u201c a u201d u201c an u201d u201c the u201d and u201c said u201d are intended to mean that there are one or more of the elements the terms u201c comprising u201d u201c including u201d and u201c having u201d are intended to be inclusive and mean that there may be additional elements other than the listed elements as.