The Breakthrough Clean TechnologiesA(R) AR15 Lower Block with Pivot Lock is designed for seamless firearm maintenance. By inserting it into the magwell, it provides a snug, secure fit, effortlessly locking in place using the receiver's magazine lock. This block can be easily clamped onto any vise, enabling convenient and stable cleaning and maintenance. It features an integrated hammer stop tool, safeguarding the receiver from damage during dry firing. As a bonus, this block comes with a Pivot Lock, ensuring easy access to the barrel and chamber. Elevate your firearm care with Breakthrough Clean TechnologiesA(R) AR15 Lower Block tool, guaranteeing a tight and secure fit for all your maintenance needs.Product FeaturesEASY CLEANING & MAINTENANCE: Streamlines the cleaning and maintenance process, ensuring convenient & efficient firearm care.INTEGRATED HAMMER STOP: Safely permits dry firing without causing any damage to the receiver, adding an extra layer of protection during maintenance.PIVOT LOCK INCLUSION: Comes equipped with a Pivot Lock feature, facilitating easy access to the barrel & chamber, enhancing the cleaning experience.SECURE MAGAZINE LOCK FIT: Provides a tight and secure fit within the magwell, locking firmly in place using the firearm's magazine lock mechanism.VERSATILE VISE CLAMPING: Allows for easy attachment to any vise, providing a stable platform for thorough cleaning and maintenance.WARNING: To engage the gun's magazine lock, either remove the hammer stop or ensure the bolt is locked back. DO NOT close the bolt with the hammer stop inserted in the vise block. This ensures safe & proper use during maintenance.WARNING: To lock into the gun magazine lock, either remove hammer stop or lock back the bolt. DO NOT close bolt with hammer stop inserted in the vise block. Clamp to any vise for cleaning & maintenance.