Otis ar vent hole scraper 5.56x45/.223< FEATURES-Easily attaches to the charging handle-Provides a quick & easy clean-Prevent oil blowback by properly cleaning the fouling that can accumulate in the tiniest of places, such as the area where the gas tube enters the upper receiver in an MSR/AR rifle Other Features: Prevent oil blowback by cleaning the area where the gas tube enters the upper receiver on an ar-15.Attaches to the charging handle and provides a quick and easy clean