A method for regenerating a filtering device is disclosed. The second mudguard member is attached to the first mudguard member below the first mudguard member. In addition, high efficiency of energy conversion, excellent field-effect mobility, good onoff current ratios andor excellent stability can be observed, when the polymers according to the invention are used in organic field effect transistors, organic photovoltaics and photodiodes. The rail splice includes indicia for setting the gap distance between rails based on ambient temperature at the time of installation.