Crucial Mac Pro Systems (Late 2013) 32GB (2 x 16GB) DDR3 1866 (PC3 14900) ECC Registered Memory For Mac Pro Systems Model CT2K16G3R186DM System Specific Memory - Newegg.com
Amazon.com: Crucial 16GB Kit (8GBx2) DDR3 1866 MT/s (PC3-14900) EUDIMM 240-Pin Memory For Mac Pro Systems (Late 2013) CT2K8G3W186DM : Everything Else
Amazon.com: Crucial 8GB Single DDR3 1866 MT/s (PC3-14900) EUDIMM 240-Pin Memory For Mac Pro Systems (Late 2013) CT8G3W186DM : Everything Else
CRUCIAL 8GB 240-Pin SDRAM DDR3 1866 Memory for 2013 Mac Pro, CT8G3W186DM | eBay