Walter Pederson received a US patent dated April 7, 1925, that covered the concave face on this iron. Pederson theorized that the convex face would impart backspin to the ball by causing the ball to roll up the face. Needless to say, few people bought in to his theory which explains why so few convex face irons remain today.
The back of this head is stamped "Pat. Pend., Pederson Mfgs., Mount Vernon, NY, Mashie" along with "BK", the owner's initials. The shaft and grip are original.
TCA2 V1 p288