An endoscopic instrument includes a housing having shaft extending therefrom that defines a longitudinal axis therethrough. The shaft includes an articulating portion disposed thereon. An end effector assembly operatively connected to a distal end of the shaft configured to treat tissue includes a pair of first and second jaw members. A locking tube is coaxially disposed on the shaft is movable along the longitudinal axis. The locking tube is movable along an outer surface of the shaft from a retracted position such that the shaft may be articulated transversely across the longitudinal axis, to an extended position such that the shaft is locked in a fixed position along the longitudinal axis.