Tired of your thread protector or high dollar suppressor working its way loose on your threaded barrel?  Don't lose your can during firing - add a suppressor retainer O-Rings to your barrel setup.
This is not your standard rubber O-Ring, these thin low-profile O-Rings are made Viton ( fluorocarbon elastomer ) and can withstand temperatures from -15 degress to 450 degrees fahrenheit. The material is also resistant to cleaning solvents, oils and other chemicals that will break down regular rubber O-rings. The retainer O-ring is not visbile when your thread protector is tightened into place and are perfectly sized to prevent movement. 
Sold in packs of 5