Hello. I'm posting to see if I can learn some info on a stopwatch I found with my deceased grandfather's belongings. I have no idea how old it is, but it's a Heuer and it looks very old. The main thing that stands out is the numbers count down instead of up, and it starts with a 0 instead of a 60. There's no serial number that I can find on the outside, and I don't want to force it to see what's on the inside. It's still in working order. I would appreciate any knowledge anyone can give me about it. Thank you.