I second the Impact Sports. Usually, I use some foam plugs and those....
While doubling up is a fine idea, I've used the Howard Leight electronic earmuffs alone on indoor ranges with no problems.I don't find the Sports by themselves are adequate unless I am shooting in an open field.
Not something I've noticed with the Howard Leight earmuffs.I haven't had any experience with the electronic muffs, but some reviews talk about there being delays before the amplification cuts out. Is that common behavior?
+1 about that.IF you are shooting indoors or shooting handguns or high-powered rifles, I would add plugs to go with whatever muffs you decide on