Sargent #3407 Type 2 Transitional Smoother. This is the smallest of the Sargent transitional line. It’s like the metal counterparts, the Sargent #407 and the Stanley #2.
Note the Sargent design has machine screws holding the frog to the frame. Others have wood screws directly into the wood base. This make for a better design in my opinion. It provides a more solid support for the frog, and the machine screws will not loosen like the wood screws.
I don’t believe it’s possible to use this plane without smiling.