From 1978 here is a superb working Seiko calculator watch C153-5007.  You'll be lucky to find a better working condition version, almost immaculate. With manual brochure, and new battery. Original straps.

I'm UK-based, and if any non-UK-based buyers want to bid, it is on the strict proviso that the buyer takes liability for any postage issues. I have had too many non-UK-buyers saying the item was lost.

Please do ask any questions, and happy bidding.