RARE A. Johanssen & Co. Marine Chronometer "Makers to the Admiralty"

See photos for condition detail.

No box and I don't have a key to test it but physically it appears to be in great condition.

56 hour marine chronometer.

Manufacture at 149 Minories, London.

S/N 8577

Weighs almost 8 lbs without packaging.

Edit: I added some photos showing the movement. Message me if you need anything more specific. Thanks.

I'm not an expert with chronometers and I was told the movement may not be original so please use your best judgement and expertise when bidding.