User interface and locking feature part for positioning multiple components in body

The invention relates to a user interface and a locking feature part for positioning a plurality of components in a body. Some embodiments are disclosed, including apparatuses, systems, and methods for positioning electrodes. In one exemplary embodiment, an apparatus includes a primary electrode defining a lumen, an elongate secondary electrode slidably receivable within the lumen, and a sheath configured to slidably receive and convey the electrode toward a target area. A housing is coupled with the sheath and is movably mounted to actuate the sheath relative to a target area. A primary actuator is coupled with the primary electrode and slidably coupled with the housing to actuate the primary electrode relative to the sheath. An auxiliary actuator is coupled with the auxiliary electrode and movably coupled with the main actuator to be capable of sliding in cooperation with the electrode. The auxiliary actuator is rotatable independently of the main actuator to travel along a helical path to actuate the auxil