Abstract: An improved indicator for fill content of a fire extinguishing system including a pressure vessel having an outlet through which the fire extinguishing material may flow. The indicator includes a non-magnetic, closed housing, mounted on the vessel and having one end within the vessel and the other end exteriorly of the vessel. At least one of the vessel and the housing are sealed to the atmosphere and a visual access opening is provided on the exterior end of the housing to allow one to look into the interior of the housing. A tape is mounted within the housing for movement in a path past the visual access opening and includes indicia along its length.

Abstract: A fire extinguishing system including a vessel having an outlet normally sealed by a frangible seal. A probe is aligned with the seal and is mounted for movement in a path intersecting the seal and spring biases the probe toward the seal in the path. A restraint is provided for normally restraining the probe in the path to prevent breakage of the seal and includes a radially outwardly opening annular groove in the probe, a series of spherical elements disposed such that they partially enter the groove, and a movable cam which abuts the spherical elements oppositely of the groove and which is configured to cam the elements partially into the groove.