Lenovo Thinkpad Battery 57+, 0C52863 6 Cell Lithium-Ion Battery Compatible for W541, W540, T440p, T540p, W540, L440 and L540 Systems. Lenovo 6 Cell 57wh , 5.2Ah, 10.8v Thinkpad Battery 57 + (0C52863, 45N1144, 45N1145, 45N1147, 45N1149) Factory Sealed Genuine Lenovo ThinkPad Retail P/N ; 0c52863- Thinkpad Battery 57+ (6 Cell)-used in Thinkpad Models ; L540, L440 , T540p, T440p, W540, W541 All Lenovo Model Numbers Are Suffix Specific. Lenovo Battery 57+ Is Not Used in T440, T440s, T540, T540S Lenovo Battery 57+ Is Safeguarded With A Chip To Authenticate Itself With Lenovo Systems. Lenovo Battery Reset May Be Needed If Your System Is Not Recognizing The Item. Remove And Re Install The Item To Fix This Issue. This Is Due To Recent Windows Updates. When Searching for a Lenovo Replacement Battery - Search by the Number on your old battery that is in the Red Circle.