Lenovo 4G DDR3 memory module.
Lenovo 4G PC3-12800 DDR3-1600NON-ECC
HP 4GB (1x4GB) Single Rank x4 PC3L-12800R (DDR3-1600) Registered CAS-1
Hypertec 00D4970-HY memory module 16 GB 1 x 16 GB DDR3 1600 MHz ECC
Hypertec HYMAC8908G-LV memory module 8 GB 1 x 8 GB DDR3 1600 MHz