1927 Zais Watch Chronographe. Spiral scale Telemetre enamel dial.

ZAIS Watch was one of the brands registered for G.Leon Breitling SA.

Between the two World Wars, plenty of watch brands supplied timekeeping tools to military forces, many Zais Watch Chronos were used by the Luftwaffe.

A tachymeter scale measures how fast an object is moving. The Tachymeter scale is the Spiral red scale on this Zais Watch Chronographe. Most tachymeters start at 400 and end at 60, but some models can show different numbers. Its very simple to calculate the speed: just mark a point and push the start button. After the object has moved for one kilometer (or mile), push the stop button. The number indicated by the hand shows the speed of the object.A telemeter scale on this Zais Watch measures the distance between the user of the watch and the event seen and heard. It was used extensively to calculate when artillery fired. When you saw the light of the shot of the artillery, you would push the start button and push the stop button when the thunder was heard. The number shown in the scale refers to the distance.

A telemeter scale on this Zais Watch measures the distance between the user of the watch and the event seen and heard. It was used extensively to calculate when artillery fired. When you saw the light of the shot of the artillery, you would push the start button and push the stop button when the thunder was heard. The number shown in the scale refers to the distance.