HP/Compaq ProBook Series Notebook Memory Upgrade Configurator - choose your Model:

4210s (DDR3)
4310s
4320s
4321s
4410s
4410s (DDR3)
4411s
4411s (DDR3)
4415s
4416s
4420s
4421s
4425s
4510s
4510s (DDR3)
4515s
4520s
4520s (DDR3)
4525s
4710s
4710s (DDR3)
4720s
5220m
5310m
5320m
6440b
6445b
6450b
6455b
6540b
6545b
6550b
6555b