Tru-Flate 17-351 1/4" Female NPT Direct Air Line Chuck With Shut-off Direct air line (closed), ball foot air chuck for general commercial and industrial air filling applications. Brass construction Maximum pressure rating of 150 psi 1/4" female NPT connection Direct air line (closed), ball foot air chuck for general commercial and industrial air filling applications. Maximum pressure rating of 150 psi 1/4" female NPT connection