Japan patent database uses F-term (File forming term) to retrieve patents by viewpoint and item code in a more precise way. Feature transfer is used to combine the strong feature 2 in alternative system to the base system with strong feature 1. The way to choose alternative system with strong feature is usually ad hoc and thus confuses new learners of feature transfer. It is the goal of this research to solve this dilemma. F-term is applied to feature transfer to find the proper alternative system with strong feature 2 in a systematic way. This research uses a muffler as an example to apply the excellence of F-term in the TRIZ’s feature transfer. There are two features, reduce noise and reduce back pressure, in the feature transfer of muffler. The basic system of the feature transfer is the improved muffler, which is characterized by the spiral turbulent tubes used to reduce noise. Whereas the competing system with strong feature in reducing back pressure is Japanese patent JP2010-065535, exhaust system of engine. The alternative system is found by the F-term 3G004DA01, and keyword: back pressure. Keywords: File forming term, reduce back pressure, reduce noise, alternative system, muffler.