Altar II: a 4.75mm-thin fully mechanical keyboard, two years in the making

Altar II is a pre-launch mechanical keyboard whose main claim is thinness: a 4.75mm chassis that undercuts even non-mechanical slim boards like Apple’s Magic Keyboard. The trick is a custom ‘dual steel arm scissor switch’ with a 40gf actuation and a preloaded tension spring mounted laterally instead of vertically, shrinking key travel to 1.8mm while keeping a mechanical feel. It’s a 75% layout with a full function row, arrow keys, and a Mac-oriented modifier arrangement, built by a small three-person team over roughly two years.

The design leans hard on extras. A detachable, swappable magnetic rotary control (M-Dial) handles volume and playback, and the company says it will publish 3D files and specs so users can print their own. A built-in haptic engine and speaker provide tactile and audio feedback for typing, notifications, and system events, configured through a native Swift macOS app; settings persist on the keyboard itself so they travel across machines. Firmware runs on the open-source ZMK/Zephyr stack, and connectivity covers dual Bluetooth 5.0 LE channels plus USB-C, with claimed 30-day battery life and macOS and Windows support.

The notable caveats are commercial rather than technical. Altar II doesn’t exist as a shipping product — audio and specs are drawn from pre-production hardware, and it’s slated for a Kickstarter launch on 10 November 2026. The page pushes a fully refundable $1 reservation to lock in a $249 price versus a later $349, so readers should treat the thinness and battery figures as vendor claims until independent units are tested.