Logitech MX Keys technical glossary

Scissor switch mechanism: Low-profile keyboard mechanism used on MX Keys: a plastic X-shaped hinge guides the key's vertical motion. Combines the slimness of a membrane keyboard with the precision of a guided mechanism. Typical lifespan: 20 million cycles per key.
Rubber dome: Bell-shaped silicone piece under each key creating tactile resistance and click feel. When pressed, the dome deforms and bridges two electrical traces on the underlying membrane. Progressive fatigue (rare before 5 years) is the main cause of mushy feel.
Hinge clip (scissor hinge): X-shaped plastic piece that clips between the key and the keyboard, guiding vertical motion via 4 articulation points. The most commonly broken part on MX Keys (around year 4 of heavy use). Universal across the MX Keys range, sold individually at €5.
Keycap: The visible plastic piece you press, bearing the printed character. On MX Keys, keycaps are made of dyed POM plastic with laser-engraved characters. Removable and replaceable individually with a fingernail or spudger.
Stabilizer bar: Horizontal metal rod present only under wide keys (spacebar, Shift, long Enter). Prevents the key from tilting when pressed off-center. Often overlooked when replacing long keys — verify it is properly clipped in both holders.
Logi Bolt: Logitech's proprietary USB receiver (since 2021), replacing the older Unifying. Uses end-to-end encryption (AES-128) certified for enterprise environments (FIPS 140-2). Compatible with MX Keys S and recent Logitech accessories. Not interchangeable with Unifying.
Unifying receiver: Logitech's historical USB receiver (2009-2021), recognizable by the orange asterisk logo. Allows pairing up to 6 devices on a single dongle. Limited security compared to Logi Bolt. Progressively replaced but still supported on 2019 MX Keys.
Easy-Switch: Logitech feature on MX Keys (buttons 1, 2, 3) allowing instant toggling between 3 paired devices (PC + Mac + tablet for example). Combines Bluetooth multi-device and Logi Bolt. Switches in <1 second without re-pairing.
AZERTY / QWERTY / QWERTZ: European keyboard layouts. AZERTY = France and Belgium (first 4 letters). QWERTY = English (US, UK, Spain, Italy, Portugal). QWERTZ = German (Germany, Switzerland, Austria). Differences in some letter positions and special characters. Each MX Keys is dedicated to one layout — not interchangeable post-purchase.
Actuation force: Pressure (in grams) required for a key to register a keystroke. MX Keys = 60 g mid-travel, comparable to a premium laptop keyboard. Lower value = faster typing but less precision.
PCB (Printed Circuit Board): The keyboard's motherboard: a printed board hosting the controller, radio module (Bluetooth + Logi Bolt), USB-C charge management, and traces connecting each key. On MX Keys, the PCB sits under the metal plate. Replaceable for €15 in case of major failure.
LiPo battery (lithium-polymer): Battery type used in MX Keys: flat, lightweight, capable of holding 1500-2000 charge cycles before degradation. Sensitive to extreme temperatures (<0°C or >45°C). Fire risk if punctured or crushed — handle with care. Typical lifespan: 4-6 years under heavy use.
Adaptive backlight: Individual white LEDs under each key, driven by an ambient light sensor. Lights up when the hand approaches, dims after a few seconds of inactivity. Reduces battery consumption vs always-on backlight. Present on MX Keys and MX Keys S, absent on K950.
USB-C: Universal charging connector on recent MX Keys (MX Keys 2019+, MX Keys S, MX Keys Mini). Reversible standard, supports fast charge. Replaces the older micro-USB of K950 and older keyboards. Data + charge cable required (not charge-only) for initial pairing.
Bluetooth Low Energy (BLE): Low-power Bluetooth variant used by MX Keys for wireless. Consumes 10× less than classic Bluetooth, enabling 5 months of autonomy without backlight. Compatible with all recent OSes (Windows 10+, macOS 10.13+, iPad/iPhone, Android, Linux).
Debouncing: Algorithm filtering electrical bounces when a key is pressed. The metal contact bounces for ~5 ms; firmware detects those bounces and merges them into a single press. If debounce is miscalibrated or the scissor is tired, the key can register twice ("double-typing").
HID (Human Interface Device): Standard USB protocol for input devices (keyboard, mouse, joystick). All modern OSes support HID natively without additional driver. That's why an MX Keys works immediately on Mac, Linux or Windows without installing Logi Options+.
SMD soldering: Surface-Mount Device: electronic assembly technique where components are soldered directly on the PCB surface. The backlight LEDs, radio module and USB-C controller of MX Keys are SMD. Individual replacement requires specialized tools (microsoldering).
Torx T5 screw: 6-point star-shaped screw, size 5 (very small). Used by Logitech to assemble MX Keys. Requires a dedicated Torx T5 screwdriver — T4 or T6 won't fit. Available in any iFixit opening kit or smartphone tool set.
Spudger: Soft plastic flat tool, designed to unclip components without scratching or short-circuiting. Used to remove MX Keys keys and detach broken hinges. €1 each in our catalog. Preferred over metal tools which scratch or short-circuit.