You do not need a special back cover to use this battery
This package is specifically designed for the watch we list here, if your watch is not in the list , then it's not for you.
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1)300mAh Excellent Replacement Li_ion Battery:
* Brand: Unbranded/Generic .
* High quality Li-Ion battery.
* Battery Type: Lithium Ion.
* Battery Capacity: 300mAh .
* Voltage: 3.85V.
* This battery is internal battery with pipe line,it has an integrated microchip that prevents overcharging and lengthens battery life.
* Best Replacement for the original battery with comparable standby and talk time .
* Our battery is sent out with little or no power, so please charge it for about 6 - 12 hours before using.
* Each battery comes with a special chip to protect your watch from over-heating, short-circuit, over charging or over discharging.
* Integrated microchip prevents overcharging and lengthens battery life.
* When using the battery, please notice that use up all the power of battery for the first three times before charging, and then take a full charge, thus the battery can be reached the optimum effect of using.Please remember that its full performance and longevity is only achieved after 3 to 5 complete charge and discharge cycles.
* Replace your existing watch battery with a stronger.(The battery operation time depends on conditions .such as: Transmitting power level, Signal (distance between the watch and the base station),Network parameters defined by the operator.)