Special tool for easy extracting blocked glow plug.
Different application, works with Mercedes, Audi , Seat , VW , Opel , Peugeot , Renault and others with M8x1.0, M10 x 1.0, 1/4NF28 ( 6.3 mm)
Frist extract the connection elctrode from the glow plug, than take centering shaft for position the 3size driller to drill out the plug. The rest of the plug can be removed by using the pull out tool
To protect against damage - e.g. if tip of the glow did not move out completely ( that can happen if tip had blown up to bigger diameter) please inspect the cylinderhead well before restart engine !