This product is either discontinued or we cannot get that from suppliers.
G.SKILL FA-10666CL9S-4GBSQ, 204-Pin DDR3 SO-DIMM, For Apple Notebook, 4GB, Speed DDR3 1333 (PC3 10666), Cas Latency 9, 1.5V.
Designed for Apple’s Mac systems, the G.SKILL DDR3 SO-DIMM for Mac series is hand-tested for compatibility, reliability, and stability - all in the G.SKILL memory tradition.