The Spitfire Chassis Indicator is one of the most sought after instruments to get hold of, namely because it is so rare and therefore commands a high price. Contrary to popular misconception, it was not made solely for the Spitfire, but did in fact appear on the panels of other Supermarine aircraft of the era.

I produce the Indicators in two versions, a fully-functional version, with working blind and lights, almost indistinguishable from an original, as on this page, and a dummy version, still made to outstanding quality, but without the working blind or back that houses the lights. Both units have exactly the same UP and Down screens which will light up if required.

This is the fully-functioning version with working sprung blind and wired-in correct spec bulbs. It also comes with the correct AM stamp on the side. I'm not aware of anywhere else that produces these.
 
Being a simple wiring unit, I see no reason why this couldn't be used in a flighing aircraft, but as with everything on my site, no airworthiness is implied or given. Please make your own checks as necessary under whatever authority governs your flight activity.