I would like to share my personal experiences of Citizen Promaster AS4020-44B here. The clock I've bought in a watch shop in Palma de Mallorca in the autumn of 2011. I liked the clock really liked the brown leather strap right away. The case diameter is 45 mm and the height of proud 16 millimeters and weighs 110 grams. Although it is housed no complex mechanical movement but a very modern technology. The wireless technology in conjunction with solar cell and a lithium ion battery, I found very impressive at this clock. It runs the years to the exact second and does not consume batteries. The energy required relates converts on the Eco-Drive, the light through a solar cell into electricity. Even if the clock gets no light over weeks and months, it passes thanks to the lithium-ion batteries continues. The power reserve is loud Citizen 1 year long. The clock also features a stopwatch function, self-luminous pointer. As befits a good Pilots, this clock has a built-in Flight Computer. The sitizen Promaster is up to 200 meters water resistant. Should his plane even need to perform a ditching, at least the clock stops completely. I own the Citizen Promaster AS4020-44B with a brown leather strap. Through daily wear of the clock, sees the band already correspondingly worn out. The housing and the glass see but like new. The clock is really very un-susceptible to wear and tear. I am the Citizen Promaster Pilot Watch really pleased and can recommend them without hesitation!