A surgical instrument includes a body member and a leg having a first end integrated with and extending from the body member. A head cavity is in the leg portion to hold a head. A channel is formed along a longitudinal length of the leg. An elongated rocker assembly includes an elongated lever arm coupled within the channel about a fulcrum and a spring actuation. A projection of the arm projects in a direction of the head cavity. A rocker slide lock has a collar slidably coupled around the body member and having a first position located between the body member and the actuation tab, such that a portion of the collar is under the actuation tab to limit pivotal motion of the rocker assembly, and a second position having a clearance from under the actuation tab.