Item #: SCP-356
Object Class: Safe
Special Containment Procedures: Due to the extremely valuable nature of SCP-356, it is to be stored in a triple locked biometric security vault at all times. [See Addendum]
SCP-356 is currently stored in a basement vault at the International Committee for Weights and Measures in France. It is contained under 2 heavy glass jars under vacuum, and is only accessible to personnel with a security clearance of 1 or higher.
Description: SCP-356 is a small fist sized cylinder that has been brightly polished. It was found in 1800 at a [DATA EXPUNGED]. It is made of an unknown metal that is indestructible and harder than diamond. It is also a perfect conductor of electricity, but stays at a constant temperature of 30 degrees Celsius.
However, that is not the most astounding feature of SCP-356. Extensive tests regarding the weight of SCP-356 has revealed it to weigh exactly one (1) kilogram (Kg). By using SCP-356, the international standard for SI weight's was made as exact as possible, and several copies of SCP-356 are kept with SCP-356 in the same vault.
Addendum: Due to the increased amounts of access requests coming to Site 19 for SCP-356, it has been loaned indefinitely to the International Committee for Weights and Measures, located in France. Personnel are discouraged from requesting time off to "Check up on SCP-356". Dr. ████