Look at the Howard Leight brand Impact Sport muff. I have and use several pair. They are quite thin and still work very well.
+1
I used a Peltor 6 for many years but they started to fall apart, even got new ear cushions but they wouldn't stay on. Tried Howard Lieght and have not regretted it. The batteries last longer too. The thin Caldwell work reasonably well but are noisy.
