Apple iMac 21.5" (Late 2009) - Core2Duo 3.06Ghz - macOS High Sierra - 8GB RAM - 500GB HD - iMac - Catawiki
Timetec 16GB KIT(4x4GB) Compatible for Apple DDR3 1067MHz / 1066MHz PC3-8500 CL7 Dual Rank for iMac (Late 2009 21.5-inch / 27-inch) SODIMM Memory MAC RAM Upgrade for iMac 10,1 and iMac 11,1 at Amazon.com
16GB (4GBx4) Team High Performance Memory RAM Upgrade For iMac “Core 2 Duo” 3.06 21.5-Inch (Late 2009) MB950LL/A iMac 10,1 1. The Memory Kit comes with Life Time Warranty. at Amazon.com
Install memory in an iMac - Apple Support
Memory Upgrades for Apple iMac 2009 - Up to 32GB
Memory RAM Upgrade for Apple iMac 21.5-inch Late 2009 4GB DDR3 SODIMM | eBay
ESUS IT Memoria RAM Upgrade 4GB para Apple iMac 20" & 24" Early 2009 & Apple iMac 21.5" & 27" Late 2009 DDR3 1066MHz SODIMM : Amazon.es: Informática