Originally Posted by bulgie

Yeah, inch-pitch. Looks low-miles, maybe even just shop-grime on a new chain? Some collector/restorer will probably pay decent money for it. Do you have a full bike's worth?
You can check for wear by measuring the full length, hanging from a nail at one end so gravity straightens it out. You don't need the length per se, but how far the last pin is past the nearest inch-mark. If all the pins fall exactly on inch-marks, then the chain is new or very low miles. A worn-out chain is something like 1/8" longer per foot, though you can still ride them like that.

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