These were volume-license keys. They allowed 16+ simultaneous logins from a single IP. While technically "top" in volume, they are notoriously difficult to use on modern home networks without specific emulators.

: Physical copies used printed stickers, while modern versions purchased via the Steam Store handle activation automatically without a visible "key" unless specifically requested for third-party integration. How to Find Your CD Key

This review evaluates a purchase (standard for versions like 1.4 or 1.6) based on reliability, activation experience, and game value. Quick Verdict: Highly Recommended for Classic FPS Fans