A 50-year-old patient complains about missing of the 37, 36, 45, 46, 47 teeth. The 35, 38, 44, 48 teeth are intact and stable, their crowns exhibit anatomic form, sufficient height, relative parallelism. Fulcrum line typically goes through the 35 and 44 abutment teeth. What fixing element should be used in a clasp denture supported by the 35,44 teeth?