If you buy and sell 7" Records?,a good idea is to use the ones you receive again.Take the stiffener,or another piece of strong Card,and put it OVER your address front side,then tape the four sides together,stiffener & Mailer,in brown tape.The buyers address can then be placed on the stiffener.I have done this for many years now,and NEVER had any complaint whatsoever,quite the opposite,and it's not only money saving,it's recycling!!,so it must be a good thing?.Good luck with it,Murray

Done that way,a stiffener on the OUTSEIDE is just as good as one on the INSIDE,and it enables recycling and saves costs on buying MORE 7" Mailers.If you buy and sell LP's?,you can also do the same thing with that size of Mailer.