For an HDMI splitter with 4 input ports and 1 output port, supporting up to 4K resolution at 60Hz, you're likely looking for a device that can handle high-quality video signals and distribute them to multiple displays. Here are some features to consider:

1. 4x1 Port Configuration: This means the splitter has 4 input ports, allowing you to connect up to 4 HDMI source devices (such as gaming consoles, Blu-ray players, or streaming devices) simultaneously. It also has 1 output port to connect to your display or TV.

2. 4K Resolution Support: Look for a splitter that supports 4K Ultra HD resolution (3840x2160 pixels) at 60Hz refresh rate. This ensures compatibility with modern 4K TVs, monitors, and projectors, providing crisp and clear video quality.

3. HDMI 1.4 or Higher: Ensure that the splitter complies with HDMI version 1.4 or higher standards. HDMI 1.4 supports 4K resolution at 30Hz, but for smooth motion and gaming, HDMI 2.0 or later is recommended, as it supports 4K at 60Hz.

4. HDR Support (Optional): If you want to enjoy High Dynamic Range (HDR) content, make sure the splitter supports HDR pass-through. HDR enhances the contrast and color range of images, resulting in a more vibrant and lifelike viewing experience.

5. Audio Formats: Check if the splitter supports various audio formats, including Dolby Atmos, DTS:X, and LPCM, to ensure compatibility with your audio setup and to maintain high-quality sound output.

6. Remote Control or Switching: Consider whether the splitter comes with a remote control or manual switching options. This allows you to easily switch between input sources and control the device from a distance.

7. Build Quality and Durability: Look for a splitter with a sturdy build and reliable connectors to ensure long-term durability and reliable performance. Heat dissipation features may also be important to prevent overheating during extended use.

8. Compatibility: Ensure that the splitter is compatible with your HDMI source devices, displays, and cables. Check for HDCP (High-bandwidth Digital Content Protection) compatibility to ensure seamless playback of copy-protected content.