Aeschbach WW2 Pattern Germany Luftwaffe / Reichsluftfahrtministerium (RLM) Pilots Watch with Sapphire Box Crystal and 21 Jewel Automatic Mechanical Movement 18mm Strap it has two lights at

it has two lights at the 12 o'clock position

Sapphire crystals are strengthened through a heat treatment process that removes internal stresses and are then coated with two layers of anti-reflective coating

United States

therefore it will not deteriorate even during heavy usage although it can be destroyed if the buclke is badly damaged by a piece of metal being gouged out or if it's worn down by really heavy abrasion against rocks or something similar

including Seiko

Aeschbach WW2 Pattern Germany Luftwaffe / Reichsluftfahrtministerium (RLM) Pilots Watch with Sapphire Box Crystal and 21 Jewel Automatic Mechanical Movement 18mm Strap it has two lights atSKU Code: ABACH DUHR2S This automatic, self winding military watch is a faithful reproduction of a classic World War II Aeschbach* design. It features a shatterproof and scratch resistant sapphire crystal, a small subsidiary second hand dial, and retains the timeless style used by the German Luftwaffe during the war. Originally issued to Luftwaffe pilots by the Reichsluftfahrtministerium (RLM German Air Ministry) on a mission by mission basis, these