Introduction
This manual provides comprehensive instructions for the setup, operation, maintenance, and troubleshooting of your SteelSeries Apex M400 Illuminated Mechanical Gaming Keyboard. The Apex M400 is designed for performance, featuring SteelSeries QX1 Linear Mechanical Gaming Switches and blue LED backlighting.

Figure 1: The SteelSeries Apex M400 Illuminated Mechanical Gaming Keyboard, showcasing its full layout and blue LED backlighting.
Package Contents
Verify that all items are present in your product packaging:
- SteelSeries Apex M400 Keyboard
- Quick Start Guide (QSG)
- SteelSeries Stickers

Figure 2: The SteelSeries Apex M400 keyboard as it appears in its retail packaging, indicating included items.
Setup
Connecting the Keyboard
- Unpack the SteelSeries Apex M400 keyboard from its packaging.
- Locate an available USB port on your computer.
- Insert the USB connector from the keyboard into the USB port. The keyboard is plug-and-play and should be recognized automatically by your operating system (Windows 10 or later recommended).
- For optimal cable management, route the keyboard cable through the integrated channels on the underside of the keyboard to exit from the center, left, or right side.

Figure 3: The underside of the Apex M400 keyboard, illustrating the integrated cable routing channels for organized cable management.
Operating Instructions
Key Features
- SteelSeries QX1 Linear Mechanical Switches: These switches provide a smooth, consistent keystroke with a linear feel, designed for rapid actuation.
- Blue LED Backlighting: The keyboard features individual blue LED backlighting for each key, enhancing visibility in various lighting conditions.
- Anti-Ghosting and N-Key Rollover: The Apex M400 supports 100% anti-ghosting and 104-key rollover, ensuring every keystroke is registered accurately, even during complex key combinations.
- Media Controls: Utilize the function (Fn) key in combination with the F-keys (F5-F12) for quick access to media playback controls (play/pause, stop, previous, next, volume up/down, mute).

Figure 4: A close-up of a keycap, showing the Kailh mechanical switch and the blue LED illumination beneath it.

Figure 5: An exploded diagram illustrating the internal components of a mechanical switch, including the keycap, stem, spring, and housing.
Customization with SteelSeries Engine
The SteelSeries Apex M400 is 100% programmable using the SteelSeries Engine software. This software allows you to:
- Remap individual keys.
- Create and assign macros.
- Adjust backlighting settings (if applicable, based on software features).
- Create custom profiles for different applications or games.
Download the latest version of SteelSeries Engine from the official SteelSeries website (steelseries.com/engine) for full customization capabilities.
Maintenance
Cleaning the Keyboard
- General Cleaning: Use a soft, lint-free cloth slightly dampened with water or a mild cleaning solution to wipe down the keycaps and chassis. Avoid excessive moisture.
- Dust Removal: Use compressed air to remove dust and debris from between the keycaps.
- Deep Cleaning (Keycaps): For thorough cleaning, keycaps can be carefully removed using a keycap puller (not included) and washed with mild soap and water. Ensure keycaps are completely dry before reattaching.
Caution: Do not immerse the keyboard in liquid. Avoid using harsh chemicals or abrasive materials, as these may damage the keyboard's finish or components.
Troubleshooting
Keyboard Not Responding
- Ensure the USB cable is securely connected to both the keyboard and the computer.
- Try connecting the keyboard to a different USB port on your computer.
- Test the keyboard on another computer to determine if the issue is with the keyboard or the original computer's setup.
- Restart your computer.
Keys Not Registering or Ghosting
- The Apex M400 features 100% anti-ghosting and 104-key rollover. If you experience issues, ensure the SteelSeries Engine software is up to date.
- Clean the affected keys as described in the Maintenance section to remove any debris that might be obstructing the switch.
Backlighting Not Working
- Ensure the keyboard is properly connected and receiving power.
- Check the SteelSeries Engine software for any backlighting settings that might be turned off or set to a very low brightness.
Specifications
| Brand | SteelSeries |
| Model Name | Apex M400 |
| Item Model Number | 64555 |
| Switch Type | SteelSeries QX1 Linear Mechanical Gaming Switches |
| Backlighting | Blue LED Backlit |
| Anti-Ghosting | 100% Anti-Ghosting |
| Key Rollover | 104-Key Rollover |
| Connectivity | USB |
| Hardware Platform | PC |
| Operating System | Windows 10 (and compatible with earlier versions) |
| Dimensions (L x W x H) | 44.04 x 13.64 x 3.96 cm (approx. 17.34 x 5.37 x 1.56 inches) |
| Weight | 1.7 kg (approx. 3.75 lbs) |
| Material | Composite with Reinforced Steel Back Plate |
Warranty and Support
For detailed warranty information, technical support, and frequently asked questions, please visit the official SteelSeries website:
You can also find product registration and driver downloads on the support page.





