Very rare WWII Germany Air Force military watch ( Big Pilot ) RLM Nav. B-Uhr . RLM stands for Reichsluftfahrt ministerium . Nav.B-UHR means Navigation Beobachtubgsuhr. RLM made between 1939-1945 era . Usually for Germay Air Force wore outside the military jacket. 55mm! Lemania made . Sn 192299 dated 1943. Accurate and original as it should be .

This is a very rare 2000 made Nav.B-UHR RLM by other Swiss pocket movement n this one famous Lemania ! Besides five manufacturers like IWC , A Lange , Stowa ,etc , only four manufactures ( Lemania, Universal , Leonidas and Minerva) used pocket movement to make the Nav B-Uhr. Pls read carefully the below website :
https://pt.scribd.com/document/384503092/Navigational-timepieces-of-the-Luftwaffe

Other references :
https://www.the-saleroom.com/en-gb/auction-catalogues/gardiner-houlgate/catalogue-id-srgard10158/lot-2d31357b-f2b9-435f-89c6-ac4d00eec6e8#lotDetails

This one is very famous Lemania made. Accurate and original as it should be . Hand wind ( can run around 40 hrs) and accurate within 1 min . eBay got one A Lange selling at 140000 while one IWC ( limited to 1000 pieces ) selling at 340000! And only 2000 totally made by Lemania , Universal Geneva , Leonidas and Minerva! Very rare to find . Watch only. Price firmed. Bought a new strap ( Jurgens , original hand made Germany military Strap 26mm for this masterpiece, Jurgensgermany.com