This is a replacement base for the Fire & Smoke Marker by Trek3D6.

The provided base is flat on the bottom, which makes placing it on a tank hull problematic, as the majority of the plastic tanks have a small raised ring for a magnet or turret plug.  I designed a replacement base that is the exact same size as the original base, but includes a circular cutout on the bottom for the ring in the turret, allowing easy placement of the marker on a destroyed tank.