Research completed to date clearly indicates that the operational requirements necessary to commercialize heavy-duty trap oxidizer technology cannot be met with available filter systems. This is why Daimler-Benz and Mann & Hummel have worked together to develop a new type of filter technology, where threads of ceramic fibers represent the filtering medium.The results obtained so far are promising. However, problems still remain with this technology. The main problem is not mechanical strength and thermal resistance, i.e. trap durability, as it is with other technologies. Rather the trap still has insufficient capacity for soot and non-regenerable particulate matter, which results in too high a regeneration frequency and an unsatisfactory useful service life.