genial : Lifetime warranty, we offer return or replace if it has any problem.specification 1. DC 9V battery -LRB- battery included -RRB- 2. photoelectrical for advance detection from all directions 3. deafening > 85dB -LRB- A -RRB- alarm 4. Flash alarm -LRB- cherry LED -RRB-. . . Test for unproblematic recommended time unit testing 6. deep battery 7. Safety clip, not allow mounting of smoke alarm without battery installed 8. Ceiling 9. Easy to with mounting bracket, battery powered, no wiring needed 10.10 years life time .