Zyxel USG FLEX 500 UTM Bundle Firewall The USG FLEX 500 offers a comprehensive cloud-based management platform while simultaneously extending and enhancing protection-from firewalls to access points-with automated responses. The newly designed USG FLEX series is capable of minimizing computing power consumption and maximizing firewall performance. It delivers up to five times the UTM performance with the flexibility of the cloud and collaborative protection to connect and secure small and medium-sized businesses.