The Bedrock frog extends through a much larger slot milled in the sole of the plane, providing support to the iron almost to its cutting edge.
This adjustment is made to vary the opening at the "mouth", which refers to the position of the cutting edge in relation to the front of the slot in the sole, and which is supposedly used to control the size of shaving taken by the plane.
However, the fact that no vintage planes are ever found with a closed throat indicates that craftsmen of old made use of this feature in extremely rare occasions.
Modern irons from other makers are much thicker, which means more material to remove, and are 100 percent tool steel, hardened to about Rockwell 62.
Of course, these are priced at multiple times more than basic Bailey pattern planes which were the preferred option for most craftsmen until the crafts began to disappear.