I've had these for 9 months now. I had no problem finding jars they would fit - you just need to get the ones with a removable centre panel in the lid. The size of these appears to always be the same. I was delighted with them in September, when I first got them, but as time passed they appeared to stop working gradually, and I even tried replacing the rechargeable batteries, as performance was poor even on sunnier winter days. Since about mid-spring, however, they are back to being fantastic. They light up each evening at dusk and are still shining brightly when we go to bed. If you buy these in the knowledge that they probably won't do much for about 3 months in the winter then I don't think you'll be disappointed.