I think their exact frequency is 32,768 (= 2**15) Hz, so that dividing
by 2, 15 times will count seconds. If this will work for you then
buying one of them might be a very cost effective way to pick one up
easily. If you can't find one there, I think I have one which I
salvaged out of a dead watch.

Thanks for the offer Jim, I have quite a few of those crystals already, but
they aren't suitable for this application which requires 32KHz not 32.768.

73 Hans G0UPL
http://www.HansSummers.com