Mid 2007 iMac cpu upgraded from t7700 to t8300 and now I have Mojave : r/mac
Sostituzione disco fisso nell'iMac Intel EMC 2133 o EMC 2210 da 20" - Guida di riparazione iFixit
2nd HDD SSD Caddy, for Apple iMac Mid-2007 20-Inch Desktop Computer A1224 Core 2 Duo 2.0 2.4 MA876LL MA877LL, Second 2.5" Hard Disk Drive Enclosure Adapter, CD DVD SuperDrive Optical Bay Replacement :
Installing a SSD drive into a mid-2007 iMac | mages' blog
2nd HDD SSD Caddy, for Apple iMac Mid-2007 20-Inch Desktop Computer A1224 Core 2 Duo 2.0 2.4 MA876LL MA877LL, Second 2.5" Hard Disk Drive Enclosure Adapter, CD DVD SuperDrive Optical Bay Replacement :
20-Inch iMac (2007-2008) Hard Drive Installation Video (iMac7,1 iMac8,1) - YouTube