4.2″ Bluetooth ESL E-ink Display Tag


Bluetooth ESL, e-ink display label tag

KESL042C(R) series Bluetooth ESL tags with high definition displays can be adapted to any sales scenarios. It supports text, promotion, QR code or barcode and can be reused with no paper required. It can be used for different application, such as the retails, warehouses and logistics management, production line, etc.

KKM Bluetooth ESL platform is a complete hardware-software system combining Bluetooth5.0 wireless communication and ESL tags, in-store navigation, ultra-low power displays, merchandising supports and tools and server infrastructure (cloud, chain-store or in-store). KKM provide SDK/API, which is open to the third-party technologies and enables interconnection with any situation software or system. It offers the flexibility you need to anticipate and overcome any challenge.

No light pollution
Black, White, Red, Yellow color available
Li-Ion Batteries
Bluetooth 4.0/5.0 wireless communication
400×300 pixels full graphic,
E-Paper displays
Cloud or local Server based options

Bluetooth 5.0

BLE 5.0 technology, automate your business, proximity marketing, indoor navigation, production line management 

Low Power Consumption 

BLE low power, ultra long battery life, reduce your maintenance cost

Open API 

Open API to integrate to 3rd party software/backend/backend

Convenient & Automative 

Manage multi stores/place just once click, reduce your labor cost and maintenance cost   

Compatible with Gateway & App 

Patented algorithm, you can update the ESL display via Gateway, smartphone or other BLE enabled device, such as Raspberry pi 

Superior readability 

Near 180°viewing angle, various of display template and sizes available, partial area refresh/update, different picture node play mode  


4.2 inch Bluetooth ESL Electronic Shelf Label

Screen Size4.2 inch (diagonal)

External (W x H x D) Visible screen area (W x H)

4.05 x 3.62 x 0.31”

83.0 x 62.0mm (3.27” x 2.44”)

Display Pixels 400 x 300 (120,000)
Dots per inch (DPI)95
Display TypeBlack and white Colors

Bi-stable EPD(E-ink Display)

Black, white and Red Colors

Bi-stable EPD(E-ink Display)

OrientationLandscape or Portrait
Viewing angleNear 180°
AppearanceStandard unit available with white frame
Unit identifier barcodeRecognized by Scanner or Labeling on back
Operating temperature Range 0°C to 50°C, +32°F to 122°F
Storage temperature range-20°C to 70°C, -4°F to 158°F
FittingsSupported by multiple fitting options – stands, adapters, individual long-length shelf-rails. Additional specialist fittings also available upon request.
Communications2.4G wireless
BatteryLi-Ion Battery 850mAh, 3.0V 
Work time2~3years(3 times refresh per day)

Frameoclors available

 Yes (MOQ applies)

3.2 Access Point (AP)


Communication2.4G BLE5.0/BLE4.0 wireless
Number of KGateway1C CoverEach covers 1000 ESLs
Covered distance100 meters, Suggested 30m (Radius)
Size173.0 x 90.0 x 56.9mm
Working Temperature-10°C ~ + 60°C
Power supplyDC +5.0V or POE
Port to Server4G, WIFI or Ethernet cable
Installation wayScrew

4. Why KESL Label

Bluetooth beacon function

• It can set and record the location of different commodities to facilitate the management.

Error is less than 1m.

• Can expand new functions by developing APP. For example, APP will choose the best way

and guide customers to the commodities that they are searching for.

 ESL Cloud

• ESL Cloud system is a cloud server based complete solution with hardware and auto-

updating software.

• All ESL tags can be controlled anytime and anywhere with cloud server.

• All data can be shared on the cloud.

Superior readability

• High Contrast: Use E-paper display with black and red on ‘paper-white’ background.

• Near 180° viewing angle with excellent

readability, compare to CH LCD ESL:

API interface

• We can provide API interface to the third-party, whom can strengthen managementability by embedding our ESL into their own system, and providing more powerful, flexible and competitive solution to end customers.

• Combine ERP with ESL perfectly to make products more competitive.

Viewing angleNear 180°120°
Contrast Ratio20:18:1
Custom-made Template design

• It’s easy to edit and create display templates.

• You can use any font in your system. It also

enable any combination of text and images including QR code, Bar code, logos, pictures, etc.

• Negative explicit mode and special symbols

are available.


• ESLs available in a range of different sizes and specifications to suit all requirements across an

entire retail estate.

• Monitoring. It will give a warning when it is out of power or be stolen.

• It can be customized with many functions to

enhance customers’ experience.

5. FAQ:


How many ESLs can be managed?

It is no limit. But it will affect the updating speed if there are too many labels to be managed, We suggest each KESLGateway/base station manage 1000 ESLs.


Can I make custom content display on the ESLs?

Yes, we will provide the development kit. The development kit includes the instruction&tools to create the content, source code of these tools, and API.


How to establish relationship between ESL and AP?

You don’t have to establish the relationship between ESL and AP. You just need to follow the instruction and implement the AP to your platform/software. 


Is there a solution that can indicate the discount for customers with a certain distance?

Yes, there is. For example, we can provide both ESL with LED light and with RED Color.


Can I use phone App instead of AP?

Yes, you can use phone App or other Bluetooth device (such as Raspberry pi) which support BLE4.0/5.0. 


What’s the next after I bought the ESL system?

We provide API, demo and tools to create display template and implement to your own software/plaftorm.