8 of 8 people found the following review helpful
Useful for smoke alarms!,
Verified Purchase(What is this?)
This review is from: Duracell MN1604 Plus Power 9v Batteries, 2 Batteries (Accessory)
And they do last quite some time too.
Not a lot to say about a pair of 9v batteries, but I've not had any problems with Duracell for this purpose.
Whilst there are quite a few rechargeable 9v ones around you are better off with these as the rechargeable types are not suggested for use in devices such as this.