This is a Schalenkreuz-Anemometer overhauled by the German Air Service's Flugzeugmeisterei and marked "No. 552." The scale is 0-20 which corresponds to a maximum airspeed of 200 KPH. The glass is etched with a semi-transparent "P.u.W." with a winger propellor; P.u.W. stood for Prüfanstalt und Werft, the testing station and workshop section. The Flugzeugmeisterei repaired German instruments and, in so doing, replaced or re-surfaced the original maker's dial card with their own name and markings. German Air Service anemometers were of two distinct designs, one high speed for single-seater scouts and the other low speed for two-seater aircraft. The housing for the dial is faired on the high-speed model but isn't on the low-speed design. This is the low-speed model.