The
Heat-Treated Castle Nut screws onto the AR15/M4 lower receiver extension
(buffer tube) and keeps the receiver extension and lower receiver end
plate secured in place. The large notches allow for positive engagement
with a castle nut wrench for proper installation and torque. The
smaller notches provide a location for the end user to stake the castle
nut to prevent accidental loosening.
Finished in a Mil-spec manganese phosphate.
Made in the USA.