The Adapter is a 85W rated power supply and replaces apple md506b/a laptop charger. Designed to meet Apple's original specifications. The Replacement Apple AC Adapter is designed to be 100% manufacturer compatible and will meet OEM specifications.Always put first the DC output plug into the laptop's power jack before putting the input plug on the power outlet. This is the correct method.Keep your adapter in a dry place with room temperature. Just like other electronic devices, adapter can get damage cause by high temperature.Always put first the DC output plug into the laptop's power jack before putting the input plug on the power outlet. This is the correct method.Replacement For Apple MD506B/A Adapter is rated at 20V 4.25A 85W.The high quality laptop charger for apple md506b/a provides your laptop with safe and reliable power.It is over Charge protection, Voltage protection, Temperature protection, Short circuit protection, enjoys 1-Year Warranty,60-Day Money Back!Brand New Replacement For 85W 20V 4.25A Apple MD506B/A AC Adapter/Power Supply/Charger With Laptop Cord.Replacement laptop AC adapter is guaranteed to meet or exceed original laptop AC adapter.Full 2 hours burning test; 3 times quality check and 2 times drop test by QC before package.Warranty and Guarantee: 1 year warranty, 60 days money back.