Smoke alarms (Leasgill LA7)

I have three smoke alarms to give away. They are about 3-4 years old. Expected life from new is 10 years. They can be used separately or they can be mains linked - 3 core and earth wiring needed for interlinking. They contain the back-up batteries - 9 volt Duracell - which are still putting out the full 9 volts.