The Franco Belge Belfort back/rear fire bricks are a Genuine Franco Belge Clay fire brick designed to help protect the side of the stove from excessive heat and will also ensure better combustion and heat retention within the fire box.
 
Installation Instructions:

Installing the Franco Belge Belfort rear Fire bricks is extremely easy and can be completed in around 5-10 minutes.
 
Remove the Throat plate , Fuel Retainer and any side and rear plates from the stove.
Before Removing the original bricks take note of the position in which they are fitted.
Replace the baffle and lift the baffle to the top of the fire box and place the side brick into the stove and bring the baffle down to the bricks.