GN405 Robust versatility and customization. The versatile GN405 is the lightest professional-class headset, offering an unbeatable array of customization options. It’s the cost-effective, yet robustly customizable solution that can be deployed across any enterprise to maximize employee productivity and comfort. GN405 Flex G N 4 0 5 SF G N 4 0 5 UNC SF The three-in-one GN405 offers customization options thanks to its three interchangeable wearing styles: earhook, earloop and headband.