Replaces OEM # L20C4P71, L20M4P71, L20D4P71, 5B10W13972, 5B10W13973, 5B10W13974, 5B10W13975, SB10T83216, SB10T83217, SB10T83218 Fits: LENOVO THINKPAD X1 CARBON GEN 9, X1 CARBON GEN 9 20XW, X1 CARBON GEN 9 20XX, X1 YOGA GEN 6, X1 YOGA GEN 6 20XY, X1 YOGA GEN 6 20Y0, X1 CARBON GEN 10, X1 CARBON GEN 10 21CB, X1 CARBON GEN 10 21CC, X1 YOGA GEN 7, X1 YOGA GEN 7 21CD, X1 YOGA GEN 7 21CE, X1 CARBON GEN 11, X1 CARBON GEN 11 21HM, X1 CARBON GEN 11 21HN, X1 YOGA GEN 8, X1 YOGA GEN 8 21HQ, X1 YOGA GEN 8 21HR Specs: 15.44V, 3695MAH, 57WHR, 4 CELL Brand New GreenTech replacement battery - 6 Month Replacement Warranty Each products has undergone rigorous testing to ensure the correct voltage, circuit protection, stable current, low self-discharge and CE / FCC / RoHS Certified for safety