https://ihc185.infopop.cc/eve/f...6095371/m/4963968577

I bought Peter's Hampden 105 today and would like to know which mainspring it takes. It's either the 2696, or the 3696.

Hi Mike,

As this is a bridge model 1902 upwards, mainspring should be #3696, strength 6 to 6 1/2, and 18 Width.

Hops this helps?

Thanks Bila. I'll look for one.

Not sure if there's one of the right size here?
Hampden mainsprings

Thanks Evan. I was able to get a couple of Alloy ones off ebay so will have them in a few days.
The 105 is running well on my table and I don't know if it needs one as I have not disassembled the watch yet. It looks clean and is keeping really good time. Maybe someone knows this answer. To me, the 105 looks just like the 104 but without the two extra jewels. Are these essentially the same with that exception?