Oregon Toothed Blade 96-397, Simplicity 1725922, Simplicity 1736044,  1 of 96-397 and 2 of 96-398 used for a 54" deck. 

Specs

Length      16"

Center        1"

Outer          3/8"

Center to Center   2 9/16"

Width          .250

Thickness   .203

Lift               1"