Final answer:
For a 25 foot fixed ladder, a harness is often used as a safety device to protect an individual by securing them to a fall protection system.
Step-by-step explanation:
The equipment on a 25 foot fixed ladder ideally should be a safety device.
This can occur in the form of a cage when it's a fixed ladder or, in the case of climbing activities, a personal fall arrest system like a harness could be employed.
While options such as a rope and a safety net can also be parts of safety equipment in various circumstances, it is the harness that offers direct protection to an individual climbing a ladder by securing the climber to a fall protection system.