Advanced Technology Spacer - A.5.10.2255

This is a Advanced Technology Spacer, model A.5.10.2255. 

AR 15 223/5.56 Steel Muzzle Brake Jam Nut 

Features: 

Fits rifles .223/5.56mm 

Heat treated steel 

CNC precision machined 

Black oxide finish 

Corrosion resistant 

1/2x28 thread