Abstract: A turnbuckle for connecting a hollow section is provided with a catch recess, with a carrier element having a clamping edge shoulder, the turnbuckle including a housing which fits within the hollow section. The housing has a longitudinal axis with an abutment pin fixed in the housing substantially transverse to the longitudinal axis. A clamping spring is movable in a translational manner within the housing, the clamping spring having a clamping finger part formed by two clamping fingers which are movable in mutually opposite directions substantially transverse to the longitudinal axis of the housing. Each clamping finger has a clamping hook end.