Basement door extension panel. For use with Classic Series Size B and C Basement Door, Model No. Size B, (SKU 100207) and Model No. Size C, (SKU 100235). No. EXT6: Size: 6", Pkg Qty: 1, Package Type: Box No. EXT12: Size: 12", Pkg Qty: 1, Package Type: Box No. EXT18: Size: 18", Pkg Qty: 1, Package Type: Box No. EXT24: Size: 24", Pkg Qty: 1, Package Type: Box