buy 50pcs get 1 pc for free now we are a professorphonebattery manufacturer ,If you are interesteringphone battery, please feel free to contact me ! 1)Color: Grey 2)Standard Voltage: 3.7V 3)Guarantee time: 1 year 4)Normal capacity: 850mah 5)Cell chemisty PCM: Li-ion battery 6)Working temp.: -10 - +50°C 7)Double IC and NTC PCB offer over- discharging,over-charging,over-current and short-circuitprotection 8)Safety and stable: Hi-tech lithium-ion battery, undergoes drop test,smash test and acupuncture testto ensure no fire and explosion in breaking 9)Battery charging time: approx. 5 hours 10) we have half housing and full housing meet for different market 11) weight :0.025 kgs without package . 12) we have closely coopereating shipping company .