NFRS 2001 / 2002 is are a family of  100 % Polyester rib Knit Inter-liner Socks.  Foam and thermoplastic-based composites that utilise NFRS 2001 / 2002 show improved light fastness . Anti-oxidization and yellowing are less pronounced creating a hygenic environment for the  mattress.    Both  interlining socks will accommodate all 5 mattress sizes.