Review on SAFELIFE Heavy Duty Brass Air Chuck - Closed Flow Tire Inflator Chuck with Clip (2 Pack) by Jason Paredes

Closed flow cartridges must hold air when not attached to the valve stem. It appears that the check valve on one of the cartridges was not drilled properly, or the stem that touches the valve core is bent or installed incorrectly. A good cartridge has its shaft centered in the hole, while a bad cartridge is offset to allow air to pass. A good cartridge performs as advertised and looks reliable.