wil kro plane

I used a razor blade plane on balsa wood when I was building models as a kid.  It worked great on balsa, never used it on anything else.

It has two blade throats, one for flat-work and the other for curved.  As noted by Gerry it uses double-edge blades and due to blade fragility is pretty limited to softer woods. Far better than the current junk for modelling purposes.