Modesty Blocks. Fixing Blocks Ideal Fixing To Have In Your House. KW1-KW17, PA20-PA38, PA41-PA49, PA60-PA78, PH4-PH44, PH49-PH50, PO (Isle Of Wight) TR (Isles Of Scilly) ZE (Channel Isles). They Have A Variety Of Uses Such As Joining Pieces Of Wood or Chipboard Together.