Special Offer Available: www.amazon.com -- Cell type: Lithium-ion Voltage: 3.7V with built in IC to prevent over charging, over current and over-heat Six Guarantee of PowerGen Battery are, no mislabel, Grade A cell, 100% satisfactory , six months warranty, RoHS & CE complied, and premium quality. PLEASE NOTE: This Extended Life Battery will increase the size of your phone making it too large for standard fit cases. ( An Extended back cover is included)