Slightly off topic, but today I changed out the Renata 390 battery that I had bought off of Ebay back in the Fall of 2016. As Renata batteries are next to impossible to find retail in the USA I bought a Rayovac replacement as I read that they are made by Renata for Rayovac. Regardless, I paid approx. double for the Rayovac at retail.
I am utterly amazed at the accuracy of run of the mill Swatch quartz watches. I check my time against Atomic Time usually every two weeks and without fault my Swatch (as did the last one before it died) may run ½ sec. fast. Now I know that is not some scientific test, but nonetheless it is unbelievable. That's HEQ territory. This year marks 30 yrs. that I have owned a Swatch and I am as loyal as a hound.