I have small balls that work quite well. My brother had a much larger set of balls that seemed to work better for holding his bag. I figured my balls weren't holding up my pocket as well as his, so I replaced my small balls with these big balls. They don't warm at all, but radiate pure transparency. Check out these balls and you'll see what I mean. Pretty good value for money if you're looking for big balls in your bag. Oh yeah, I should probably mention that I use them for home brewing to keep the hop bags from floating.