The present invention relates to a sealing element and/or guide ring manufactured from a composition comprising: i) 50% to 98% by weight of polytetrafluoroethylene and/or modified PTFE, ii) 1% to 49% by weight of perfluoroalkoxy polymer and iii) 1% to 49% by weight of an inorganic filler selected from the group comprising charcoal, graphite, glass fibers, carbon fibers, molybdenum disulfide, metals such as copper, alloys such as bronze, ceramic particles such as aluminum oxide and any desired mixtures of two or more of the aforementioned substances.

A method for producing a piston for internal combustion engines, where the piston includes a circumferential trapezoid annular groove for receiving trapezoid rings with small axial dimensions the groove having a groove base with adjoining surfaces and groove flanks. The groove base with adjoining surfaces is created in a first method step by machining using a cutting steel tool and the groove flanks are created in a further method step. Also disclosed are a piston produced according to the method and a cutting steel tool.