When making your purchase please use the
drop down box to choose one of the following options:

CB for Corrugated Back 

WH for Williams & Hussey, Shop Fox W1693, W1739 and W1812
        Bridgewood 704, Grizzly G0552, G0488

SB for a set of 3 knives, 1/4" thick, smooth steel for 
        Grizzly G1037, G0477, Belsaw, Powermatic 15 
        and similar machines.

SB1 for a single 1/4" thick knife with Gibs and
        counter weights for Foley-Belsaw and 
        similar machines.