4GB (1x4GB) DDR3-1866MHz PC3-14900 2Rx8 SODIMM Laptop Memory by NEMIX RAM at Amazon.com
A-Tech 4GB Replacement for HP 708633-B21 - DDR3 1866MHz PC3-14900 ECC Unbuffered UDIMM 2rx8 1.5v - Single Server Memory Ram Stick (708633-B21-ATC) at Amazon.com
G.SKILL Ripjaws X 32GB 16GB 8GB 4GB DDR3 1866MHz PC3-14900U Desktop Memory LOT – ASA College: Florida
12GB (1 x 4GB + 1 x 8GB) PC14900 DDR3 1866MHz SO-DIMMs 204-Pin Memory Upgrade Compatible with 2015 (Late) iMac 27" w/Retina 5K Models and PCs (OWC1867DDR3S12S) at Amazon.com
Used HP Additional 4GB 1866 MHz DDR3 ECC RAM Memory E2Q91AT B&H