The IBS Stabilizer Unit is designed to block the internal barrel of the G&G ARP 9/556 to avoid any vibration that could cause deviations and important inconsistencies in the trajectory of the ball. Once installed, the performance of the rifle will improve notably, firing more straight. and further with a proven enhancement in bundles · The IBS is designed to be easily installed · One of the easiest but most effective enhancements you can make to your Airsoft rifle