Energizer Ultimate Lithium 9V Batteries (2 Pack), Lithium 9 Volt Batteries

Customers find these batteries work well, particularly for smoke detectors, and consider them the best lithium ones available. The battery life receives mixed feedback - while some say they last a lot longer, others report they don't last nearly as long as advertised. Value for money is also mixed, with some customers finding them worth the high price while others disagree.