These are CNC made in Europe with high quality material to replace your original inserts. Price is for one piece. 
 
The concave surface of the ball is about 20% larger than the original, which gives a greater possibility of introducing the air flowing into the upper chamber into the swirl where the mixing occurs and is pre-ignited.
 
Inserts made of high quality, high temperature steel (the same steel used for cylinder head valves). They are 30% stronger than stock. These are 1 mm longer than stock so that after correct assembly, the excess pin is ground off.
They are designed for the OM605 and OM606 engines, but the dimensions are identical to the OM617 inserts, just that the shape of the ball is a little different, but our pin will work better than the original pin from the OM617.