Aerial Refueling Telescoping Boom Indicator, KC-97L Boeing Stratotanker 1952 USAF P-47 and P2 Neptunes

and P2 Neptunes

The #4 pointer appears to be loose but might be able to be re-inserted firmly

The knob itself is missing

I have located this instrument on the engineers panel of the US Navy's floatplane JRM-1 Martin Mars

indicating RPM for the rotor on the inner scale and rotor for the outer scale with a ratio of 9

Aerial Refueling Telescoping Boom Indicator, KC-97L Boeing Stratotanker 1952 USAF P-47 and P2 NeptunesThis offer is for a vintage Cold War era aerial fueling Telescoping Boom Position Indicator, made by Liquidometer PN EA 308 1, as used in the US Air Force's KC 97L Stratotanker (and likely earlier versions given its date stamp of 1952), as depicted in its Flight Manual (unfortunately the page showing the indicator does not photograph well). This indicator appeared on the boom operator's control panel and indicated the length of the refueling boom as