Emission legislation for Off Road Engines is forcing the industry to review the engine design, introducing state of the art technology for many components and tailored exhaust gas after treatment architectures. Particulate matter reduction is a crucial issue to be addressed having an influence on overall engine performance and cost. At the present stage there is not a unilateral solution in the industry, as some manufacturers use a combination of very high fuel injection pressure and very efficient DOC, while others rely on the automotive derived DPF technology with active regeneration or SCR-only technology to reach EU Stage IV and US Tier4f. Considering the pros and cons of each solution, VM Motori decided to adopt an innovative solution consisting in a DOC followed by a partial-flow filter PM-Metalit® for the R750 Engine family. The advantages of this solution will be discussed in this paper along with the application work that has been carried over to reach the emission limit. A short overview of the PM-Metalit technology will be given together with a comprehensive explanation of the physical mechanisms that allow a constant and maintenance-free PM reduction. Moreover, tests results to simulate real life conditions will be discussed.