Installation isn't dependent on a stable internet connection until it's time for activation.
While Kaspersky primarily promotes its online installer to ensure users always have the latest version, an offline (full) installer can still be obtained for faster multi-device deployment. kaspersky small office security download offline installer
You can create your own offline package by running the online installer and copying the temporary installation files from C:\ProgramData\Kaspersky Lab Setup Files before the installation finishes. Why Choose the Offline Installer? Installation isn't dependent on a stable internet connection