ULTRA LIFE, 10 year, smoke alarm battery, U9VL-X
The Ultralife 10 Year Smoke Detector Battery is the only 9V battery warranted to last 10 years.  Alkaline batteries in smoke detectors have to be changed every year.  With the Ultralife 10 Year Battery, state-of-the-art lithium technology keeps your life-saving detector energized for a full 10 years.  You can forget all those "low-battery" alarms that always seem to sound in the middle of the night.  It is a must for second homes where your smoke detector can fail when you're not there.  This battery contains no toxic metals.