Ergohaven has announced the K:04, a new split ergonomic mechanical keyboard featuring an adaptable modular design that allows users to add navigation modules to expand the keyboard's functionality beyond just typing. The K:04 is designed around ergonomics, with a 58-key layout split between two separate halves that communicate wirelessly using Bluetooth LE. The 58-key layout roughly mimics a 60% keyboard by keeping the number row and eliminating dedicated navigation keys—those are placed on secondary layers, which can be accessed with a key in the thumb cluster. Each half has three or four thumb keys, depending on how far you want to reach under your palm with your thumb. It also features a columnar stagger, which means the keys are offset vertically in order to better align them to the curvature of your fingertips when your hands are at rest and prevent straining to reach keys. The K:04 is available from the Ergohaven online shop in several different configurations, with the base keyboard without switches or keycaps coming in at $180. Adding switches and low-profile blank keycaps brings it up to $240, while adding labelled low-profile Space Encounters keycaps or sculpted keycaps brings the price up to $265 or $280, respectively.

The headline feature of the K:04 is its interchangeable input modules, which allow users to expand functionality by adding a rotary encoder, a touchpad, or a track ball to the inside edge of either half of the keyboard. The keyboard's layout and the functionality of each module are configurable in Ergohaven's open-source Entropy customization software, based on Vial, and the configured functionality of each module will remain on the keyboard's controller if the module is removed and re-enabled whenever the module is reinserted. The keyboard itself is also highly configurable, with the design being based around the Gateron LP 3.0 switch standard but also supporting full-height MX switches with an additional switch plate. Each module also adds additional cost to the keyboard, starting with the rotary encoder at $35, the touchpad at $55, and the 32 mm trackball at $65.