We ARE the manufacturer......... Detroit Muscle Technologies 
 
3/4" thick, matt faced insulation for the rear the A/C heater box of your 66-70 B body - Belvedere, Charger, Coronet, Road Runner, GTX, Satellite, Super Bee. This piece insulates the cold box from the hot firewall. 

NOTE: This piece is already included in our 66-70 B Body AC Heater Box Rebuild Kit
  

THIS GETS GLUED TO THE BACK OF THE AC HEATER BOX. SOME ROCKET SCIENTIST LEFT A NEGATIVE FEEDBACK BECUASE "HE THOUGHT" IT WAS THE WHOLE FIREWALL INSULATION. JFC!!!!!!!!!!!!!!!