Vacuum Gauge Leak Disc

Vacuum Gauge Leak Disc. ?inch and 5/16 inch apertures. A sandwiched ring of rubber on steel. Marked on one side 'LEAK DISC', Dimensions: 4" diameter. Used with 107?

Details

Category:
Tools of the Trade & Personal Accessories
Object Number:
1977-7049
Materials:
rubber (unidentified) and steel (metal)
Measurements:
overall: 95 mm,
type:
vacuum gauge leak disc
credit:
British Rail, Historical Relics