Product details:

32GB (4 x 8GB) Capacity, 1600 MHz Clock Speed, PC3-12800, 204-Pin SO-DIMM, Low Noise 8-Layer PCB, Voltage: 1.35V, RoHS Certified. Boost the memory capacity of your supported Mac with the 32GB DDR3 1600 MHz SO-DIMM Memory Upgrade Kit from OWC. This kit contains four 8GB memory modules. Compatible with 204-pin SO-DIMM slots this DDR3 memory upgrade has a 1600 MHz clock speed a bus speed of PC3-12800 and a low-noise 8-layer PCB design. Operating at 1.35V this RoHS-certified memory is designed to meet or exceed Apple's and Intel's specifications.