An ultrasonic instrument includes a body, an actuation assembly, a shaft assembly, an ultrasonic blade, and a movable member. The body is configured to receive an ultrasonic transducer. The actuation assembly includes a first activation member and a second activation member. The first activation member is operable to trigger activation of the ultrasonic blade in a first power mode. The second activation member is operable to trigger activation of the ultrasonic blade in a second power mode. The movable member is configured to move between a first position and a second position. In the first position, the movable member is configured to permit access to the first activation member and prevent access to the second activation member. In the second position, the movable member is configured to permit access to the second activation member and prevent access to the first activation member.
