This is a external thread repair tool
made by NES thread repair.
This set has the external capacity of 5/32" to 11/16".
tool will restore inch or metric, right handed or left handed
fastener threads. The floating cutters included in this set are
self-adjusting to any pitch and size within range. With these tools
there is no need for calibration or identifying thread types, and the
set automatically chases good thread sections to repair the damaged