This design, the proud result of many years of research, solves almost all ergonomic problems that occur with heavily used doors. For this reason we called it the Ergo handle. The main benefits of the FSB 7655 Ergo handle are: Its triangular alignment, which corresponds to the user's direction of movement. This angular shape accommodates the sequence of movements when opening and closing the door. Its curve and cross section, which match the form of a hand as it closes to grip. Its left/right alignment, which provides a firm hold if elbows are used to operate the door. The FSB Ergo door handle set 7655 has twist-fix bearings and is suitable for fire doors. Due to the large projection of the handles, FSB recommends using locks with a 9 mm follower. The door handle square is therefore always 9 mm.