BRTONG High Performance Replacement Battery for Apple MacBook Air 13 inch A1245, A1237, A1304 (2008-2009 Version) Compatible Models: Apple MacBook Air 13 Inch Battery Type: Li-ion; Capacity:5200mAh/37Wh; Cells:4-cell; Voltage:7.2V. Operation Time: Around 1.5-3 hours, the actual operation time will depend on how much electricity is required by the device and how you use it. About 500 recharge cycles over the life of the battery. Certification: Overcharger and Discharger Circuit Protection, CE-/FCC-/RoHS-Certified for safety. Warranty: 24 x 7 email support, 30 days money return guarantee, 12 months warranty.