These are made from a single piece of High Speed Steel ground with a very fine edge.
They are only suitable for non abrasive materials but will give a superior finish in soft timbers.
Generally HSS cutters are slightly less expensive than their TC grades but can be more suitable for certain applications.
Single flute cutters with extra long shanks.

Specification:
D=3/16 inch
D=4.8 mm
C=19 mm
OL=60 mm
Shank Diameter=1/4 inch