Which of the following is a nonmechanical firestop system?

A cable transit system is a mechanical firestop system that uses a modular frame with individually installed and mechanically secured modules to seal around cables.

Firestop blocks are preformed intumescent or ablative material units that are physically placed into cable tray openings or other penetrations without the use of mechanical components or assembly steps. Their fire-stopping performance relies entirely on the material's passive thermal reaction properties - expanding or charring when exposed to heat - rather than any mechanical action. This distinguishes them from systems that require frames, modules, bolts, or other hardware to function.

A fire rated pathway device is a mechanical solution involving a fabricated enclosure or sleeve with mechanical components that must be installed around a cable pathway.

A factory fabricated sleeve system is a mechanical firestop method that uses pre-manufactured sleeves requiring mechanical fastening into wall or floor openings during installation.