These are a replacement blades for the Glaser 404 Oscillating Hoe (Hula or Stirrup Hoe)
The Glaser oscillating hoe is made in Switzerland with typically good engineering.
This Wheeled Seeder can be used by hand or attached to the Glaser wheel hoe (or planet junior).
Goosefoot Negative hoe attachment
Goosefoot positive hoe attachment for the Wheel hoe
These oscillating /hula hoes attach to the Glaser wheel hoe ( or Planet Junior) with 2 bolts
Glaser Wheel hoe is the most efficient human powered garden tool.