Alternatively, a more sci-fi approach: Lisa is a cybernetic model with a code name. Chémal and Gegg are two other models. Set 175 might refer to a set of parameters or a mission number. The link could be a neural connection or data link between them for a coordinated task.
One rainy afternoon she slipped inside while the museum was nearly empty. The room smelled faintly of dust and cedar. Up close, the Chemal model was more intricate than she’d imagined: a lattice of glass tubes and copper coils, tiny valves engraved with numbers, and a faded label with a script she couldn't quite read. Number 175 was stamped on a brass plate, and a small, barely visible link — a loop of tarnished metal — dangled from one joint, as if waiting to be reconnected. lisa+model+chemal+and+gegg+sets+175+link