This is a 4-40 Die from K&S Engineering.
FEATURES: A must for the scratch builder, modeler, etc. Rethreads 4-40 thread pattern Intended for use on K+S Aluminum and Brass Stock
INCLUDES: One 4-40 Die
REQUIRES: Die Handle
SPECS: Thread Pattern: 4-40 Diameter: 3/4 " (19mm)
