UL AND FM APPROVED 
For fire sprinkler and other commercial piping 
Knurled swivel nut (3/8")design permits vertical hanger adjustment after installation. 
Electro-Galvanized steel construction

Blue plastic washer holds hanger and insert nut together

Nut Retention: The knurled insert nut is "captured" in the top of the hanger. This prevents the nut from falling out during installation or while the hanger is being handled.