Great product
Fits into the magwell with the bolt locked back, releases easily with a push of the mag release button. Flag is readily visible with the dust cover open, but allows the dust cover to be closed to keep debris out. Yellow bottom is always visible in the magwell, and covers it completely to keep debris out. It will not allow the insertion of a magazine, but drops free with a push of the mag release button, allowing quick loading of a magazine and loading first round by pressing the bot release
