Replaces OEM # 5B11B79217, 5B11B79218, 5B11K07736, 5B11M960061, 5M11E25313, 5M11E25314, 5M11L99160, 5M11L99161, 5M11L99163, 5M11L99164, 5M21L37921, 5M21L37922, L20D4P75, L20M4P75, SB11B79215, SB11B79216, SB11K07734, SB11M89862 Fits: LENOVO THINKPAD P1 GEN 4, P1 GEN 4 20Y3, P1 GEN 4 20Y4, P1 GEN 5, P1 GEN 5 21DC, P1 GEN 5 21DD, P1 GEN 6, P1 GEN 6 21FV, P1 GEN 6 21FW, X1 EXTREME 4TH GEN 20Y5, X1 EXTREME 4TH GEN 20Y6, X1 EXTREME GEN 5, X1 EXTREME GEN 5 21DE, X1 EXTREME GEN 5 21DF Specs: 15.52V, 90.1WHR, 5805MAH, 4 CELL Brand New GreenTech replacement battery - 6 Month Replacement Warranty Each product has undergone rigorous testing to ensure the correct voltage, circuit protection, stable current, low self-discharge and CE / FCC / RoHS Certified for safety