This is a Safe Flight Instrument Corporation Force Application Kit

Part Number
990-1-3 (Thats what it says on the box)

used to measure the lift transducer for the stall warning tab on the leading edge of aircraft.The First Gage measures .3 to 3.0 Grams –  Part Number: 34263-1The Second Gage measures  to 6.0 Grams –  Part Number: 34263-2The First Gage measures to 30 Grams –  Part Number: 34263-4 I’ve seen them sell for 6 plus grand but these are not calibrated to current. Includes the original case and instructions as shown as well as the parts book break down.