Product Detail Works with the following models: Toshiba A505-S6033, Toshiba A665-S6050, Toshiba A665-S6070 Toshiba L645D-S4030, Toshiba L655D-S5050, Toshiba M645-S4050, Toshiba PPM79U-006001 . The "Toshiba - Memory - 4 GB - SO DIMM 204-pin - DDR3 - 1066 MHz / PC3-8500 - unbuffered - non-ECC" is best product for you. We recommended Toshiba - Memory - 4 GB - SO DIMM 204-pin - DDR3 - 1066 MHz / PC3-8500 - unbuffered - non-ECC