Welcome to TsuLin:
Dear customers, thank you for your interest and support for our laptop battery. We highly suggest that Before you place the order, please check and confirm your laptop model, original battery model and appearance, compared with our battery image,make sure that's what you need.

Specification:
Model: B31N1911 Voltage: 11.55V
Capacity: 42Wh/3640mAh Battery Type: Li-ion
Condition: 100% brand new from the manufacturer
Connector: Please refer to the battery picture and compare with your original battery
After-sale service: 30-day refund, 12-month free warranty. Friendly customer service respond within 24-hour.

Replacement Part Number:
Replacement for B31N1911 C31N1911 0B200-03580000 0B200-03750000 B0B200-03580300 Battery

Compatible Models: (use "Ctrl+F to find your model quickly")
for ASUS VivoBook Flip 14 TM420IA TM420IA-DB71T TM420IA-CH71 TM420IA-DB51T Series; for ASUS VivoBook 14 M413 M413DA M413DA-EB005T M413DA-EB094T Series; for ASUS VivoBook Flip 14 TM420IA TM420IA-AP4513T TM420IA-EC056T Series; for ASUS VivoBook 14 F413 K413 X413 Series; for ASUS Notebook X X413FF X421DA X421EA X421EP A413FF F413FF K433FA V4050FA V433FA Series

Note: For more accurate, please check the part number of your original battery
Tips: Battery Maintenance Method for Optimal Use:
①　When you get the new battery, discharge the battery to 5% (not 0%), then charge and cycle 3-4 times to wake up the new battery
②　The important point is to perform a full discharge and charge every other month to extend the battery life
③　Do not connect adapter for a long time while using the battery. It may damage the battery
④　Avoid artificial shocks, disassembly, crush or puncture. Do not dispose of it in fire or water