Had not heard of it but as I read it they need to used in synch with their muffs, right? Spending money in this quest is getting old plus I'd rather not be locked into one set of muffs. And I see..... black foamies. Do you find this a super-effective combo? Would love to hear about it, and... how about using the plugs only for when you are not right up in the action but maybe 50 yards back, will the function without the muffs?