I have the older muffs, TAC-6 and two TAC-7s
The TAC-6 are behind the head the TAC-7s are over head
The TAC-6 uses two AA or AAA batteries
The TAC-7s use one 9volt battery
Both can be used with a rifle
Both cut out load noise ( gun fire )
I prefer the TAC-7 they are so comfortable I forget they are on my head
The foam rings on both are replaceable ( called a Hygiene Kit )
I have a hearing problem ( load noises damaged my ears ) and
these muffs amplify sounds so I can hear all range commands and
conversations at the other end of the firing line
My wife liked the TAC-7s so much I had to get her a set
One set was purchased in 1999 the second in 2011 and they look and operate just as good as new
I understand the TAC-7s have been discontinued
but they make a set that looks like them and have head they are
just as good