Thank you for viewing! This is the "Keychron Q1 V2 Knob Version Ultra-Silent Custom," a full-aluminum custom keyboard from Keychron, a renowned and popular brand in the mechanical keyboard world, especially their top-of-the-line Q series. Even without any customization, this model offers a top-tier typing feel and quality. This is a special edition that replaces the switches with silent ones without compromising the typing feel, making it suitable for use in offices or at night. You can customize the keymap using VIA, and you don't need to search for and download JSON files; you can change the keymap immediately by accessing VIA. 【Product Condition】 Used Sparingly: It appears to be in very clean condition. Accessories: All included. The outer box has some dents, but the contents are unaffected. Key Switches: The main 26 alphabet keys use "Akko Penguin," and the rest use "Gateron Brown." You can enjoy switching them out for a change of pace or to suit your needs. Bonus ①: Includes 5 types of test key switches. Please enjoy finding your preferred typing feel and sound. Bonus ②: Includes a natural wood palm rest. The combination of the matte black aluminum case and natural wood is very stylish. 【Specifications】 Model: Keychron Q1 V2 (with Knob) Color: Carbon Black Layout: US Layout Main Switches: Akko Penguin Silent Switch (Lubed/Ultra-Silent Tactile) Sub Switches: Gateron G Pro Brown (Brown) Features: RGB Light, Hot-Swappable, Wired Connection Accessories: Complete (cable, tools, original box) Bonus: Natural Wood Palm Rest, 5 types of test switches 【Regarding the OS Switch】 The Mac/Win physical switch on the side of the unit is fixed on the Mac side and does not respond. However, this unit is fully compatible with VIA (keymap rewriting software), so there is no practical impact. I myself used it in a Windows environment, but by setting up a keymap for Windows on VIA, I was able to use it very smartly and comfortably without operating the physical switch. If you are "primarily using it with a specific OS," you can use it without any problems.