Tier Installers are used to upgrade various machines into their Factory equivalent. Right-click on the machine with the Tier Installer and it will upgrade that machine to a Factory - its level (Basic, Advanced, or Elite) depending on the level of the Factory Installer used.
Basic Tier Installers can be used on any machine that has a Factory associated with it that has not yet been turned into one. However, Advanced Tier Installers can only be used on Basic Factories, while Elite Tier Installers can only be used on Advanced Factories, and Ultimate Tier Installers can only be used on Elite Factories. This is intended so that the player does not skip any tiers in the "upgrade chain", e.g. going from Basic Factory to Ultimate Factory instantly.
Basic Tier Installer
Advanced Tier Installer
Elite Tier Installer
Ultimate Tier Installer