Raven Concealment Systems TopStop Features The Raven Concealment Systems TopStop snaps directly onto most AR-15 or M4 type upper receivers when they are separated from the lower sealing the open end of the receiver completely. That seal keeps dirt moisture and other contaminants from entering the upper during cleaning maintenance or storage protecting the internal components from fouling buildup. Built from tough polymer the cover is designed to withstand repeated use without cracking or losing its snug fit over time. Because the TopStop only fits uppers detached from the lower it is meant for use during maintenance intervals rather than as a permanent accessory. Beyond sealing out debris the TopStop also physically prevents the bolt carrier group and charging handle from sliding out of the receiver while it is being carried or transported separately. This keeps those critical components contained and reduces the chance of losing or damaging them when an upper is stored loose in a range bag or safe. Finished in a bright Orange with a matte finish the cover is easy to spot among other gear and parts. The Raven Concealment Systems TopStop is a simple inexpensive way to protect a detached AR-15 upper during cleaning and storage. Raven Concealment Systems TopStop Specifications Manufacturer: Raven Concealment Systems Model: TopStop Compatible Hosts: AR-15 Uppers Color: Orange Finish: Matte Material: Polymer Available At: GrabAGun