If you are new to using a suppressor, Strike highly recommend users to get in the habit of checking for concentricity. Their set of Alignment Rods are made out of carbon fiber and this set comes with rods for multiple calibers such as: .22LR/5.56mm, 7.62/.300 Blackout, 8.6mm/.338 Lapua, 6.5mm., 9mm, and .450. Use these tools to verify that your suppressor is properly aligned with the barrel of your firearm to avoid baffle strikes or other serious malfunctions or accidents. Strike chose to use carbon fiber for its precise and durable nature, (within 0.003″ straightness tolerances) making these rods perfect for use with a wide variety of firearms. Carbon material is also safer for the inner bore of your barrel compared to steel rods. These also happen to be very lightweight so taking them with you to the range isn’t much of a burden at all.