The Instrument Source Warning Indicator for Vacuum Systems. The kit connects to the vacuum gauge via a tee fitting. The kit is NOT STC'd.
Is this vacuum failure warning light kit FAA TSO'd for use in certified aircraft?
Per the supplier: No, this is not FAA Approved for use in certificated aircraft. A 337 field approval would need to be filed for a certified aircraft. The warning light kit is normally installed as a minor modification not requiring an STC.