The Duracell Ultra Alkaline D Batteries Pack Of 2 provide high performance for everyday use devices like radios, high power toys, big flashlights/torches, etc. They have Duralock technology that locks the power of the battery cell even when stored for ten years (in ambient storage condition). The 1.5V battery cells are made leak-proof and they perform over a wide range of temperature without getting spoiled. It guarantees long lasting power and reliable usage. They are much more efficient than ordinary zinc carbon batteries.