Abstract: Temperature of a blood bag or other refrigerated package is continuously monitored throughout long periods of low temperature transportation and/or storage by an attached button. If the package contents exceed the predetermined safe upper temperature limit, the button produces an indication of having exceeded such limit sometime during transportation and/or storage. The indication is provided by a visual marker mounted on a metal part having a phase transition temperature corresponding to said limit and formed above the safe temperature to have a position which holds the indicator in a visible position corresponding to excessive temperature. The wire is shaped to a second position at freezing temperatures below said safe temperature by means which provide a visual indication of such setting.

Abstract: A locked enclosure may be eventually automatically unlocked by a simple pin element in a hasp-lock which drops out of the hasp-lock in case of temperatures associated with a fire.