That’s the “Root Slayer” made by Radius. You can find them on Amazon for $50 and it’s a very impressive product. I’ve used it for three collecting seasons now, and have also been digging out some 30 year old rhododendron from my landscape with it, and the blade is still sharp, the teeth on the sides work as a saw for thick roots, and the joint where the plastic meets the metal is incredibly strong, allowing for much more leverage and torque than you can put on any other shovel I’ve ever used. Plus it will be a go to if there is ever a zombie apocalypse. Nothing but good things to say about it and I just bought a second one for a non-bonsai buddy who likes to join me on collecting trips.