Energizer's new 9V-size battery is available in a bulk pack. The chemistry is lithium primary, and the voltage is 9V. These batteries last for as long as 10 years, are guaranteed not to leak, and are 1/4 smaller in terms of weight than a common alkaline 9V battery. They also have a lifetime that's 20% longer than the Energizer Max 9V battery when put into toys, and can operate in temperatures ranging from -40 degrees F to 140 degrees F. A common use for these 9Vs is in smoke detectors and carbon monoxide detectors. It must be said that Energizer's Advanced Lithium batteries are being phased out in favor of these Ultimate Lithium cells.