How can I tell how old my Gruen watch is?

Gruen Curvex Year of Production: 1942 10k Gold filled case, approximately 36 mm in length, approximately 25 mm in width (excluding crown) Thickness 9.8 mm Rug width: 16mm The crown winds and sets smoothly Strap Material: New genuine brown leather strap Dial Color: champagne dial good conditions, with luminous numerals. Movement: Cal.440 Curvex Manual winding Crystal: Original clean high dome curved crystal Quite good general conditions In its glory years from the 1920s through the 1960s, the Gruen Watch Company of USA & Switzerland was one of the leaders in wristwatch design and quality, even collaborating with Rolex from...

FACTORY / HOUSE: Gruen Watch Company STYLE / REFERENCE: Art Deco / Cushion Shape METAL / MATERIAL: White Gold-Filled CIRCA / YEAR: 1931 DIMENSIONS / SIZE: Length 25mm X Width 27mm MOVEMENT / CALIBER: Manual Winding / 15 Jewels / Caliber 115 DIAL / HANDS: Enamel Print Dial with Arabic Numeral Markers / Blued Steel Hands ATTACHMENT / LENGTH: Original Period Leather, Strap and Buckle, 16mm / Regular Length WARRANTY: 18 months on the movement This is a "vault find" watch, it has been locked up for nearly 50 years, which means it needs a service. We will give it a factory quality service by our finest watchmaker as part of the purchase price before it is shipped out to you. This will delay shipping for a few days of course. LIFETIME SERVICE COMMITMENT This great looking and dependable watch by the renowned house of Gruen is in nearly new condition. It is done as a classic cushion shape because it looks like a pillow cushion. The watch is all original, dial and hands with beautiful blued steel hands. The dial is done in Sterling Silver with Kiln Fired Enamel Printing and was produced by the legendary house of Stern Freres. Stern was the major dial maker in Switzerland at the time and supplied dials to the finest Swiss houses. In fact in the early 1930's Stern purchased the world's most famous watch company, Patek Philippe from the bankruptcy court. The Stern family still owns Patek Philippe today. If you cannot afford a Patek, you can own a watch with a dial by the owners of the company. And, you can wear this watch all the time for all sorts of occasions. The watch is fitted with what appears to be an original period strap and buckle. The strap is too fragile to be worn however but we offer the watch with a new Lizard Strap and the original buckle as well. Founded in 1894 by Dietrich Gruen. The company had their American base in Cincinnati, Ohio, and it produced a wide variety of watches, including pocket watches...

FACTORY / HOUSE: Gruen Watch Company STYLE / REFERENCE: Art Deco Tonneau METAL / MATERIAL: White Gold-filled CIRCA / YEAR: 1925 DIMENSIONS / SIZE: Length 28mm X Diameter 35mm MOVEMEN...

FACTORY / HOUSE: Gruen Watch Company STYLE / REFERENCE: Art Deco / Octagon METAL / MATERIAL: 14Kt White Gold Filled CIRCA / YEAR: 1928 DIMENSIONS / SIZE: Length 37mm X Diameter 30mm...

FACTORY / HOUSE: Gruen Watch Company STYLE / REFERENCE: Art Deco / Tank Style METAL / MATERIAL: 14Kt. Solid Gold CIRCA / YEAR: 1930 DIMENSIONS / SIZE: Length 37mm X Width 23mm MOVEM...

A vintage find and in its original condition, enjoy this circa 1940's Pan American Wrist Watch with Veri Thin movement developed and manufactured by Gruen Watch Co. An American base...