Our brand new 34Wh(11.4V, 4700 mAh) Original Lenovo L13M4P21, L13L4P21 batteries are made with high quality cells ( SANYO, BAK, SAMSUNG etc.), lasting as long as the original battery did. All of our Li-ion replacement batteries for Lenovo Yoga have been tested and proven to match and/or exceed original battery performance and 100% compatible with Original Manufacturer Specifications. Every piece of battery for Lenovo Yoga 220428, L13L4P21 laptop has been tested on Lenovo Yoga systems to ensure the safety for your Lenovo Yoga laptop.This high quality rechargeable battery for Lenovo L13L4P21 laptop is designed with the highest control standards; have internal circuit boards with smart chips ( Cell imbalance shut off protection, Thermal runaway protection, Overcharge shut off protection, Over discharge shut off protection, High/low temperature shut off protection ), and are made from eco-friendly materials without lead or mercury. Every replacement Lenovo L13L4P21 laptop battery has been Certified by CE, UL, ROHS, ISO9001/9002 and has passed strict safety tests. Long lasting, Lenovo L13M4P21 battery can be charged/discharged for more than 600-800 cycles.