I bought a FRSS2623AS. It does not have shabbos mode. I tried magnets, but after moving them around the entire frame, nothing turned off the lights. It's possible the magnets I'm using aren't strong enough, though they were the strongest I was able to procure in the limited time I had before shabbos.
The options mentioned upthread don't seem to be available anymore. Zman technologies is only for ge and Shabbat Pro seems to be defunct.
Is there another option? Does anyone know about this device particularly and where exactly the magnets would need to be placed?