Sony Ericsson BST-36, Z550c, Z550i, Z558c, Z558i battery.

Replacement Sony Ericsson BST-36, Z550c, Z550i, Z558c, Z558i battery pack for ; J300, J300a, J300c, J300i, K310a, K310c, K310i, K320, K320i, K500, K510a, K510c, K510i, T270, W200, W200a, W200c, W200i, Z310, Z310a, Z310i, Z500, Z550a and more.

Replaces Sony Ericsson 3.7-volt BST-36 mobile phone batteries, please fully charge battery pack before first use and after next 5 or 6 uses to maximise the capacity, also before any period of storage.

This battery pack fits the Following Sony Ericsson Mobile Cell Telephones:
Sony Ericsson ; J300, J300a, J300c, J300i, K310a, K310c, K310i, K320, K320i, K500, K510a, K510c, K510i, T270, W200, W200a, W200c, W200i, Z310, Z310a, Z310i, Z500, Z550a, Z550c, Z550i, Z558c, Z558i

chemistry battery type is & Li-ion or Lithium Ion
Voltage of battery is 3.7v

Battery Capacity: 750mAh (Extended battery for longer life)
Why is my Ah rating different?
The Ah (Amp Hour) Rating is the storage (or fuel) of the battery, the higher it is, the longer the battery lasts between charges, bit like petrol in your car so a higher or lower one makes no different to the performance, just the length of time you can use the battery for between charges.