1/2 UNC SLOTTED NUT BL GR5

Slotted nuts are used together with a bolt and a cotter pin to create a secure nut in place so that it cannot be tightened or loosened. In Metric these are known as Castle nuts.
Thread = 13 TPI

GST Incl
Excl
1/2 UNC SLOTTED NUT BL GR5
NSLTC012B
Each
$5.0364