Here is some information to help you with this clock.  In recent times not too many of these clocks have been auctioned or sold.  So, the value in the right market may take off and not be anywhere what I appraise this for.  Online auctions may not be the way to sell this item. I would contact NAWCC and see what they think about it. 

Following is information on the clock and some examples of the 431 Modernique.  It was produced in 1927-1928.  Art Deco.

"Telechron made their first art deco entry in a huge way.  Paul Frankl did as much as any one man to defining the style with his many, striking designs.  Telechron had him design a clock that would become the 431 "Modernique", as actively sought by deco collectors as Telechronies.  It was the only clock he designed for Telechron but within a few years, the style more than caught on--it became the de-facto standard.  Some of  most famous and prolific designers would impart their own interpretation of art deco into scores of Telechrons."

http://www.telechron.net/431.htm

http://electric-clocks.com/TCModernique/

This online appraisal is an expert's opinion of the item(s) depicted above based solely on images and information supplied by our customer. Additional information, not shown on this certificate, may have been taken into account for this online Appraisal.

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* Current Fair Market Value is the amount someone might receive when selling their item to a dealer or at auction. It is also the amount most government tax agencies (IRS, Revenue Canada, Inland Revenue, etc.) recognize as the tax deductible amount were the item donated to a charitable organization.

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