Adapter: Female 5.5x2.5mm plug on one end and male 5.5x2.1mm plug on the other. "L53" - Allows you to charge the V72 battery from the AC charger that came with your laptop. 5.5x2.1mm output. Compatible with chargers for laptops that use the 5.5x2.5 DC Output wire. Charger output must be 14-20V DC.