This tool will allow you to remove the prechamber ring on later om602 om603 diesel and turbodiesel engines that have the splined ring prechamber collars.  These came on Mercedes diesel and turbodiesel engines such as:

1990-1991 350SD 350SDL (W126)
1990-1993 300D 5 cylinder om602 (W124)
1992-1995 300SD and S350 (W140)

This tool is impact rated and can be used with any 1/2" drive impact and/or ratchet.

Seller also makes a tool to remove the prechambers themselves (which sit below the prechamber collar), and if you buy both at the same time, the seller can combine shipping for you (after the transactions are completed)