An ultra-thin module encased in carbon fiber makes for a stylish G-STEEL timepiece with the slimmest profile yet. Strong, yet lightweight, the carbon core guard structure absorbs external shocks and retains Bluetooth connectivity and solar power functionality even with smaller components and a thinner module. Measuring just 12.9mm from the back of the case to the top of the bezel, the GST-B400 is over a millimeter thinner than its predecessor . Your choice of four distinctive styles-the simplicity of a silver metal band and silver case; light silver case set against dark resin band; dial in dramatic red vapor deposition finish paired with a black ion-plated bezel; or dial in bold blue vapor deposition finish with black ion-plated bezel and band. With top bezels treated with five different finishes and middle bezels treated with four, these G-STEEL timepieces deliver exceptional metal textures from every angle. * Slimmest profile as of December 2020