Raven Concealment Systems TopStop Features The Raven Concealment Systems TopStop is built from tough polymer and snaps securely onto most AR-15 or M4 type upper receivers once they have been separated from the lower. Sealing the open end of the receiver keeps dirt dust and other debris from entering the action during transport storage or while the upper sits disassembled on a bench. That same seal also works in reverse keeping fouling and residue contained rather than spreading onto gear or other equipment. A matte black finish gives the cover a low-profile look that blends in with most AR builds. Beyond sealing the receiver the TopStop physically prevents the bolt carrier group and charging handle from sliding free while the upper is being carried or moved which is a common annoyance when transporting a disassembled rifle. This is especially useful for armorers competitors and anyone who regularly swaps uppers or travels with a broken-down rifle. The cover is designed to work only on uppers that are detached from the lower so it is not intended as a dust cover for an assembled rifle. This Raven Concealment Systems TopStop upper receiver cover is available for sale at GrabAGun for AR-15 owners who need a simple reliable way to protect a detached upper. Raven Concealment Systems TopStop Specifications Manufacturer: Raven Concealment Systems Model: TopStop Compatible Hosts: AR-15 Color: Black Finish: Matte Material: Polymer Available At: GrabAGun