S6 Engineering have released a smoke and vehicle damage marker.
From their announcement:
This new item from S6 Engineering is a simple marker to show smoke or vehicle damage. The twist is that the base can be assembled in two ways – with the small piece underneath it fits the 1″ turret rings found on a lot of vehicles giving you a very neat way to mark destroyed tanks.
There’s also a pocket for a magnet so, if you’ve magnetized your vehicle turrets, it will snap positively into the turret ring.