a valve assembly having a base and a removable latched insert that separately contains a valve piece . the valve piece is resiliently supported to abut a seal fitted to the insert . the insert is restrained to the base with a pair of resiliently biased latch arms that radiate from the insert . flanges at the latch arms are resiliently biased to flex and grip the base as the insert is pushed into the base . insert removal is effected with the release of the latch arms and a lifting of the latch arms .