Razer Cortex is a Windows application for game optimization and management. An "offline installer" is a full installer package you download once and run without needing an active internet connection during installation.
The Offline Installer is a standalone package. razer cortex offline installer
Installation Process:
C:\Program Files (x86)\Razer\Razer Cortex).Cortex.exe.can feel like a gatekeeper rather than a helper. While Razer primarily pushes its web-based Razer Central Razer Cortex offline installer — steps & download