CK721 - Keyboard COOLER MASTER - Free user manual and instructions

Product type	Wireless mechanical keyboard
Brand	Cooler Master
Model	CK721
Form factor	75% with arrow keys and integrated numeric keypad
Connectivity	Bluetooth 5.1, 2.4 GHz wireless (included dongle), USB-C wired
Power supply	Rechargeable lithium-ion battery (typical capacity 4000 mAh)
Announced battery life	Up to 200 hours (backlight off)
Backlighting	Per-key RGB, customizable effects via Cooler Master software
Dimensions (approx.)	31.5 × 12.0 × 4.0 cm
Weight (approx.)	800 g
Material	ABS plastic chassis, double-shot PBT keycaps, hot-swappable
Compatibility	Windows, macOS, Android, iOS, Linux
Main features	Switching between 3 Bluetooth devices, 2.4 GHz and wired mode, FN multimedia keys, Windows key lock
Maintenance and cleaning	Use a soft, slightly damp cloth; do not use solvents or abrasive cleaners. Unplug before cleaning.
Safety	Do not expose to moisture or extreme temperatures. Do not open the housing. Use only the provided cable.
Spare parts and repairability	Hot-swappable keycaps and switches. Standard USB-C cable available. Battery replaceable by a professional.
Warranty	2 years (according to local legislation)

Frequently Asked Questions - CK721 COOLER MASTER

How to connect the keyboard via Bluetooth?

Slide the switch on the side to Bluetooth mode. Use the combination FN + DEL/PGUP/PGDN for 5 seconds to pair. The indicator flashes blue. On your device, search for 'CK721' in Bluetooth devices.

How to switch to 2.4 GHz mode?

Switch the switch to 2.4 GHz mode. Plug the included dongle into a USB port on your computer. The keyboard connects automatically. The indicator turns solid green for 3 seconds if the connection is successful.

How to charge the battery?

Connect the keyboard to a USB port via the provided USB-C cable. The indicator turns red while charging. Once the battery is full, the indicator turns green. A full charge takes about 2 to 3 hours.

What to do if the keyboard does not power on?

Check that the battery is not discharged. Connect the USB cable to recharge. If the problem persists, reset the keyboard by holding FN + R for 5 seconds.

How to switch between multiple Bluetooth devices?

Use FN + DEL (device 1), FN + PGUP (device 2), or FN + PGDN (device 3) to change the connected device.

The indicator flashes red, what does it mean?

A red flashing indicator every 20 seconds indicates low battery (less than 15%). Recharge the keyboard as soon as possible.

How to customize RGB effects?

Download and install the Cooler Master MasterPlus software or use FN shortcuts: FN + arrows to change mode, FN + function keys for brightness.

The keyboard is unresponsive, how to reset it?

Hold FN + R for 5 seconds. The keyboard will restart to factory settings.

Can I replace the switches?

Yes, the CK721 supports hot-swappable switches (3-pin). Carefully remove the keycap and switch using the included tool or a compatible puller.

How to clean the keyboard?

Unplug the keyboard. Use a soft, slightly damp cloth (water) to wipe the surface. For areas between the keys, a compressed air blower or a soft brush is recommended.

USER MANUAL CK721 COOLER MASTER

CK721 WIRELESS SETUP GUIDE

EN

IMPORTANT

Please charge your new keyboard for at least 2 hours before using for the first time.

A. USING BLUETOOTH - AN OVERVIEW

B. MANUALLY PAIRING DEVICES

TO THE KEYBOARD

C. SWITCH PAIRED DEVICES

A. USING 2.4 GHZ - AN OVERVIEW

B. MANUALLY PAIRING 2.4 GHZ DONGLE

TO THE KEYBOARD

BLUETOOTH MODE

1. Isolate the pharyngeal switch on the side of
2. Press and hold FN + DEL/PGUP/PGDN for 5 seconds to enter pairing mode. The Indicator & DEL/PGUP/PGDN key will rapidly flash BLUE 3 times one every second to confirm you are in Pairing Mode.
3. If pairing is successful, the indicator & DEL/PGUP/PGDN key will light up with a solid GREEN light for 3 seconds. If unsuccessful, the keyboard will enter Sleep Mode after 30 seconds. In Sleep Mode, all the keyboard lighting will be turned off.

Turning On Bluetooth After the First Time

1. When the Bluetooth mode is activated, the keyboard will connect to the previous

2. If successfully connected, the Indicator & DEL/PGUP/PGDN key will light up with a solid GREEN light for 3 seconds. If unsuccessful, the keyboard will enter Sleep Mode and turn off the LED. The LED will then turn on again.

3. To connect to a specific paired device, press FN + DEL/PSUP/PGDN after activating Bluetooth mode to connect to the corresponding device. The keyboard will connect to the device if successful and enter sleep mode after 30 seconds if device is not found or fails to connect.

4. Toggle the physical switch on the side of the keyboard to enter Bluetooth Mode. 2. Press and hold FN + DEL/PGUPU/PCDN for 5 seconds to enter pairing mode. The Indicator & DEL/PGUPU/PCDN key will rapidly flash BLUE 3 times one every second to confirm you are in pairing mode.

5. If passing is successful, the indicator & DH/PEG/UPGON key will light up with a green light and the keyboard will turn off. The indicator & DH/PEG/UPGON key will turn off after 30 seconds. In Sleep Mode, all the keyboard lighting will be turned off.

6. Press FN + DEL/PGUP/PGDN to switch to the corresponding paired device

2.4 GHz MODE

1. Toggle the physical switch on the side of the keyboard to enter 2.4 GHz Mode. The Indicator & Enter key will continuously flash a BLUE light one every second to confirm it is trying to connect to a device.
2. Plug the included dongie into the desired device. The keyboard will automatically send the dongie to the device.
3. If successfully connected, the Indicator & Enter key will light up with a solid GREEN light for 3 seconds. If unsuccessful, the keyboard will enter Sleep Mode after 30 seconds. In Sleep Mode, all the keyboard lighting will be turned off.
4. To pair with other devices, simply unplug the dongle and re-plug into another device. If pairing is successful, the Indicator & Enter key will light up with a solid GREEN light for 3 seconds. If unsuccessful, the LED will turn off and the device will be turned off in seconds. In Sleep Mode, all the keyboard lighting will be turned off.
5. Toggle the physical switch on the side of the keyboard to enter 2.4 Glitz Mode. Press and hold PN + Enter for 5 seconds to enter pairing mode. The indicator & Enter key will rapidly flash BLUE 3 times one every second to confirm you are in Pairing Mode.
6. Plug the Included dongle into the desired device, The keyboard should automatically connect to the device.
7. If pairing is successful, the indicator & Enter key will light up with a solid GREEN light for 3 seconds. If unsuccessful, the keyboard will enter Sleep Mode after 30 seconds. In Sleep Mode, all the keyboard lighting will be turned off.

SWITCHING TO WIRED MODE

CHARGING THE KEYBOARD

A. CAPSLK Indicator

B.Wireless Mode

C. Low Battery Scenario

D. Indicator on DEL/PGUP/PGDN

WIRED MODE

If the physical switch is toggled to Bluetooth or 2.4 GHz Mode The keyboard will switch to Wired Mode automatically as the physical switch is toggled to Wired and it is connected to a PC or laptop.

If the physical switch is toggled to Wired Mode

The keyboard will switch to Wired Mode automatically as it is connected to a PC or laptop.

CHARGING

If the physical switch is toggled to Bluetooth or 2.4 GHz Mode The keyboard will remain connected to the wireless device and begin charging when it is plugged into a PC, laptop, or power source. When charging, the indicator light will be RED and the keyboard will light up with RED BREATHING lights then switch back to the GREEN mode. When the battery level is full, the Indicator light will change to GREEN and the keyboard will light up with GREEN BREATHING five times.

If the physical switch is toggled to Wired Mode

The keyboard will begin charging when it is plugged into a PC, laptop, or power source. When charging, the indicator light will be RED and the keyboard will light up with RED BREATHING five times then switch back to light mode.
When the battery level is full, the indicator light will change to GREEN for 3 seconds then turn off and the keyboard will light up with GREEN BREATHING five times.

INDICATOR LIGHT RULE

The CAPSLK indicator will light up with a solid WHITE light when turn on CAPSLK key, and turn off when turn off CAPSLK key.

1. In Paing Mode, the Indicator & DEL/PGUP/PSDN key will rapidly flash BLUE 3 times one every second.

2. In Connecting Mode, the indicator & DEL/PGUP/PGON key will continuously flash a BLUE light once every second.

3. If Connecting / Connecting is successful, the indicator & DEL/PGUP/PGDN key will light up with a solid GREEN light for 3 seconds.

4. When the battery level falls below 15%, the keyboard will enter Low Power Mode and the keyboard backlight will be turned off. The indicator will repeatedly flash RED light 3 times every 20 seconds until the keyboard enters Sleep Mode or is connected to the PC, laptop or power source.

The Low Power Mode percentage can be customized via Cooler Master software.

1. When the battery level falls below 5% , the keyboard will go into Deep Sleep Mode. All lighting will be turned off - including the indicator.

Press FN will show the pairing status of each location (DEL, PGUP or PGDN) with WHITE light.

WICHITG

© 2021Cooler Master Technology Inc. All Rights Reserved. All trademarks are registered to their respective owners. Ver 1.0: 2021/02 512004490-GP