Transcend 4GB JetMemory DDR3-1333 ECC Unbuffered DIMM 1Rx8 For Mac Pro Mid 2010 /Mid 2012(TS4GJMA343H) For Mac Pro Mid 2010 - Mid 2012 512Mx8 bit 1.5V Timing 9-9-9 Operating Temperature 0 ~ 85 C Compatible with select Mac systems. Verify model for compatibility ECC DIMM 512Mx8 bit 1333Mbps 1.5V Timing 9-9-9 1 Rank Operating Temp. 0 DegreeC ~ 85 DegreeC Compatible with selected Mac systems. Verify model for compatibility