said first mentioned guiding means including {TAIL ~ means} for slidably confining the front portions of the respective push buttons against movement away from said port member to assist in maintaining compression of said valve members and thereby maintaining sealing pressure between said valve members and said {HEAD ~ port member} 
said first mentioned guiding means including { TAIL ~ means } for slidably confining the front portions of the respective push buttons against movement away from said port member to assist in maintaining compression of said valve members and thereby maintaining sealing pressure between said valve members and said { HEAD ~ port member }
OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD