Plug of foam but it comes out. I carry five broadheads and two blunts while deer hunting or remove the foam and carry 18 blunts stumping or a mix for bunnies & small game.
On my third foam plug. I just cut a new one from the closed cell foam PCs come with (from work).
Here's a shot while bunny hunting (just after deer closed) showing how you have access to choose different arrows as needed. To push through brush you just keep it tucked up against your ribs - quiet and not bulky. I have a file on mine to touch-up broadheads.
Just noticed it's in my avatar as well. It's been a great quiver.