A surgical device includes a housing, an elongated shaft, an end effector, and an actuation mechanism. The housing pivotally supports a movable handle between unactuated, first actuated, and a second actuated positions. The elongated shaft extends distally from the housing and defines a longitudinal axis. The end effector has a pair of opposed jaw members that are movable between an open configuration in which the jaw members are spaced apart from one another and a closed configuration in which the jaw members are closer together. The actuation mechanism is configured to transition the end effector between the open and closed configurations as the movable handle is pivoted between the unactuated and first actuated positions and to maintain the end effector in the closed configuration when the moveable handle is between the first and second actuated positions.