looking right now at Cousins, checking for price of mainspring for UT/ETA 6497/8 movements...
Desired size is 1.50x0.175x440x14.5
Now take a good look,
article GR4307 cost almost twice less than GR43071 (which is declared for ETA/UT).
Now what is a difference, I couldn't find it?
Also, I think next one 1.50x0.175x480x14.5 could fit into barrel...
