When buying a LENOVO L21M3PF1 Laptop battery, you need to pay attention to the following aspects:

Battery product number: This is the unique identifier of the battery that matches your model. It is important to buy a L21M3PF1 battery with the same product number as your original one to ensure compatibility and safety.

Capacity: It is measured in milliampere-hours (mAh) or watt-hours (Wh). The higher the capacity, the longer the battery life. However, higher capacity batteries L21M3PF1 may also be heavier, larger, and more expensive. You should balance your needs and preferences when choosing a battery capacity.

Voltage: It is measured in volts (V). The voltage of the battery should match the voltage of your original battery L21M3PF1.

Price: This is the amount of money that you need to pay for the battery L21M3PF1. You should compare different options and look for discounts or promotions to get the best value for your money.

Warranty: This is the guarantee that the battery L21M3PF1 seller provides to cover any defects or malfunctions of the battery within a certain period of time. The warranty may vary from a few months to a few years depending on the seller and the quality of the battery.