ATC&reg; New Laptop Replacement Battery for TOSHIBA Satellite M55-S325 M55-S3251 M55-S329 M55-S3291 M55-S331 M55-S3311 M55 Series(except M55-S139 & M55-S139X), Replacement for PA3399U-1BAS PA3399U-1BRS PA3399U-2BAS PA3399U-2BRS PA3400U-1BRS PA3478U-1BRS PABAS057 PABAS076 , 4400 mAh 6 cells