Main Differences of Keychron Low-profile Series 

1. Keychron low-profile keyboards classification

Keychron low-profile keyboard contains 3 different series: K series, K Pro Series, and S Series.

K series low-profile keyboards: K1, K3, K5, K7

K Pro series low-profile keyboards: K3 Pro

S series low-profile keyboards: S1

2. Summary of the main differences

Table header 0K SeriesK Pro Series
Keycap typeABS shine-throughDouble-shot PBT non-Shine-through
Switch typeLow-profile Gateron mechanical/ Keychron opticalLow-profile Gateron mechanical
Case materialAluminum frame + ABS bottom saseAluminum frame + ABS bottom case
ConnectivityBluetooth 5.1 / WiredBluetooth 5.1 / Wired
QMK/VIA supportNoYes
Stablilizer stems designTriangle positionStraight line
NKRO supportCable: NKRO BT: 5/6-KROCable: NKRO BT: NKRO

3. Detailed introduction to the differences

3.1 Keycap type

       Double-shot PBT keycaps that are made of durable non-backlight shine through PBT material with excellent oil resistance, and prevent legends from fading.

Non-shine-through PBT Keycaps

       ABS shine-through keycaps provide you with a clearer view of the characters in the dark. Therefore, it is more suitable for dim typing environments.

Shine-through ABS Keycaps

3.2 Switch type

        Low-profile Keychron Optical switch uses light sensors to trigger the keystrokes. When you press the key, the stem of the switch blocks the light, and the signal is sent to the computer. It is faster than the mechanical switch.

Low-profile Keychron Optical Switches

       A low-profile Gateron mechanical switch is triggered by contact between two different conductive materials. If you select the hot-swappable low-profile Gateron mechanical switch version, you can experience different switches and typing feels very easy.

Low-profile Gateron Mechanical Switches

3.3 Case material

        The K series and K Pro series are equipped with ABS bottom case and Aluminum frame.

        The S series comes with a full CNC Aluminum Body and steel plate, it weighs more and looks more advanced and of superior quality.

3.4 Connectivity

       Both the K series and K pro series support Bluetooth 5.1 and wired modes. They can connect to three different BT devices, you can easily switch between them.

        The S series supports wired mode only.

3.5 QMK/VIA support

        The K Pro series and S series support QMK and VIA. You can program or remap the keys, create the macros, and customize the backlight. The changes remain if you change the computer.

        The K series doesn't support QMK/VIA, you need to download a third-party app to remap the keys, such as Karabiner(For macOS) and Sharpkeys(For Windows).

3.6 Stabilizer stems design

         For the K series, the stems of the large keycap(e.g.: space bar, left Shift, backspace, and Enter key) are triangularly distributed.

        As for the K Pro series and S series, they are seated on the same level instead.

3.7 NKRO support

       What are NKRO and 5KRO/6KRO?
       If your keyboard supports NKRO, you can press all the keys simultaneously, they will not interfere with each other.
       For 5KRO/6KRO, the keyboard can register 5/6 keys at the same time.

       All 3 series support NKRO on cable mode, but they are different on BT mode. The K Pro series brilliantly supports NKRO on BT mode as well.

4. Purchase suggestions

1. If you need to travel frequently, you can select the K series or K Pro series, S series comes with an aluminum body and steel plate, and is heavier than the K series or K Pro series, and it supports wired mode only, you have to carry an additional cable;

2. If you want to fully customize the keymap but don't want to change the computer system settings, the K Pro series and S series fit you better, they support VIA/QMK, and the changes are saved in the keyboard chip;

3. If you pursue cost performance, please choose the K Pro series. Compared with the S series, it is cheaper and supports Bluetooth mode. Compared with the K series, it supports QMK/VIA and has endless possibility;

4. If you are a high-end player, you can purchase the S series, it has a full Aluminum body and steel plate, which makes a more premium look and feel.