These blades are high carbon steel designed to fit the Veritas Veritas Router Plane and our Veritas Hinge Mortice Plane, as well as Stanley #71 router planes (with the height-adjustment nut inverted).
Veritas has identified a need for a range of blades from as narrow as 1/16" through to 1/4", in both Imperial and Metric measurements. An additional straight and spear point blade at 1/2" and a two piece straight blade at 3/4" are available for those larger and wider rebates and trenches.
This is a 4mm wide cutting blade.