AddOn 4GB Factory Original UDIMM for Lenovo 57Y4138 - DDR3 - 4 GB - DIMM 240-pin - 1333 MHz / PC3-10600 - 1.5 V - unbuffered - ECC - for Lenovo ThinkStation C20; C20x; D20; D30; E20; E30; S20; S30.