Starrett combination square blades are made from hardened steel and are straight to better than 0.001in per foot. Both sides of this hardened steel blade are deeply photo-engraved with full mm and 64ths on one side, half mm and 32nds on the other.

The B300-36 is compatible with all standard Starrett combination square components (excluding the smaller Junior series and larger 8 series Combination Squares).