Not sure about the ethics of this one so mods / admins please delete if you don't feel appropriate.
This is a used but (to the best of our knowledge) working Fireangel optical smoke alarm, with a marked replacement date of Feb 2029. Removed as we have upgraded to mains powered alarms, immediately stored in plastic bag to avoid contamination. No known faults, false alarms etc. No known incidents which might have contaminated the sensor. Horn sounded OK when last tested. Supplied with original mounting plate and screws (though you might want to find alternative screws, I think the heads are a bit mangled.) If anyone's interested I can probably dig out the instructions if I search deeply enough in the kitchen drawers!