RAM & Memory Upgrades
16GB (2 x 8GB) DDR3L 1600MHz PC3L-12800 204-PIN SODIMM MEMORY RAM COMPATIBLE WITH INTEL IMAC 27" RETINA 5K (LATE 2014 - MID 2015)
SIZE/CAPACITY: 16GB KIT (2 x 8GB) VOLTAGE/POWER CONSUMPTION: 1.35v CAS LATENCY: CL11 SPEED: PC3L-12800 (1600MHz) TYPE/INTERFACE: 204-PIN DDR3L SODIMM 204-PIN INTEL IMAC & INTEL MAC MINI DDR3L SODIMM
https://www.bizrate.co.uk/ram_memoryupgrades/16gb-2-x-8gb-ddr3l-oid6611193689.html