The Dinkum Systems FlareDinkum CINE Fixed Base Mount French Flag Assembly gives you the functionality of a one-flag matte box at a small portion of a matte box's cost. For most uses, one flag is exactly what's required anyhow. The assembly attaches into any 1/4" thread on your camera or rig, screwing in at the turn of a knob, and its adjustable arm will find its way, with the flag at its head, to right in front of your lens. The arm features 15 links and is 12 inches long. You can optionally add more links for more length.
You're free to remove the arm along with the flag at anytime while leaving the base mount fixed to the camera or rig. The arm just pops off of the first link on the base. As well, you're free to remove the flag only and to replace it with an optional Dinkum Clamping Top, which will hold various accessories, like microphones, up to 2 inches thick.