EXPIRY 2039. ENERGIZER AA ULTIMATE LITHIUM BATTERIES. WORLD'S NO.1 LONG LASTING LITHIUM BATTERY. WEIGH 1/3 LESS THAN STANDARD ALKALINE BATTERY. Also Known As: L91, LR91, LR6, MN1500, MIGNON, 15A, 15AC, 4006, 815, AA, AM3, E91, KAA, ND62S, STILO.