MMD KM21 Ultra vs MelGeek O2
Get the MMD KM21 Ultra for hot-swappable and knob. Get the MelGeek O2 for the 2,500 mAh battery.
The differences that matter
Skip the 40-row spec sheet. These are the specs that change how each board feels, sounds, and fits your desk.
MMD KM21 Ultra
MelGeek O2
Hot-swappable
Yes
No
Battery
980 mAh
2,500 mAh
Case material
Aluminum
ABS, Aluminum, Polycarbonate
Mount style
Top Mount
Gasket Mount
Knob
Yes
No
- MMD KM21 Ultra
- MelGeek O2
- Performance
- 6754
- Build quality
- 8265
- Productivity
- 8954
- Customizability
- 8951
- Portability
- 8683
- Layout size: Numpad
- Connection: Bluetooth, 2.4 GHz, Wired
- Sound dampening
MMD KM21 Ultra vs MelGeek O2 specs
Every tracked spec, side by side. Rows marked with a dot differ between the boards.
11 of 23 specs differ
MMD KM21 Ultra
MelGeek O2
Hot-swappable
Mount style
Sound dampening
Layout size
Layout standard
Ergonomics
Knob
Display
Connection
Max polling rate
Battery
USB-C
Case material
Plate material
Keycaps
Weight
Dimensions
Typing angle
Backlight
QMK
VIA
Mac & Windows
Released
Compare prices
Live prices from the stores we track, cheapest in-stock offer first.
Lowest price across stores, Amazon excluded.
Prices in USD are converted to your currency and can change at any time. KeebFinder may earn a commission when you buy through these links, at no extra cost to you.
Not sold on either?
Still torn?
Answer a few quick questions and the keyboard finder ranks 2,000+ boards by how you will actually use yours.