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RFID key fobs with a 125 kHz TK4100 chip
(Product ID: 1471)

Are you looking for a handy 125 kHz transponder for unlocking your doors, quickly recording a presence at work, or other identification purposes?

We offer high quality 125 kHz key fobs with the very commonly used TK4100 chip which has a preprogrammed ID and works with the majority of 125 kHz read-only RFID readers.

The TK4100 key fobs are available in multiple colors (blue, gray, black, green, red, orange, and yellow) and have a popular tear-shaped housing measuring 40 x 32 x 4.5 mm.

For orders above 100 pcs, we can do various customization services like printing company logos, serial numbers, or other personalization.

You are welcome to buy 125 kHz key fobs from stock or send us an inquiry for customized key fobs. Depending on your requests, we will help you select the best option.
Price/item: 0,74 EUR (with vat 0,90 EUR)
Status: In stock
Dispatching time: 1-3 days

Keyfobs Colour:


Product ID: 1471


74,00 EUR

Total with vat:
90,28 EUR
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Do you need print or other specific requirements?
Send inquiry


Quantity Price/pcs
≥ 1 0,84 EUR
≥ 10 0,82 EUR
≥ 25 0,80 EUR
≥ 50 0,78 EUR
≥ 75 0,76 EUR
≥ 100 0,74 EUR
≥ 150 0,67 EUR
≥ 200 0,63 EUR
≥ 300 0,57 EUR
≥ 500 0,50 EUR


125 kHz key fobs are RFID transponders in the form of a keychain and are very convenient to carry around. They can unlock the doors, pay for a drink at a vending machine, or can be used to identify users in various other RFID applications. 

There is a large supply of similar key fobs on the market, and although they all look the same, there can be very big difference in the quality and their operation.

The TK4100 chip is a read-only chip that operates at a frequency of 125 kHz. It is compatible with other 125 kHz read-only chips like the EM4200 and older variations like the EM4100 and the EM4102. It has a preprogrammed ID which is commonly read as 10-digit long decimal number or 8-digit long hexadecimal number. The preprogrammed ID cannot be changed.

Our key fob housings have a very common tear-shaped, made from plastic material (ABS) measuring 40 x 32 x 4.5 mm. They contain also a ring with which it can be attached to the keys or other accessory and are available in multiple colors (blue, gray, black, green, red, orange, and yellow). 

By default, they do not contain the numeration or other printed elements, but if you need the customization, please let us know and we will send you an offer.

Options for customization (for pricing please send an inquiry)

Beside the key fobs from stock, you can order customized key fobs with a housing in different color or shape, we can print on key fobs your company logo, serial number, or chip ID code. 

Since the chip ID code can be read in more than 50 different ways, we take extra care that we print the code in the proper format. 

Reading test for RFID key fobs with a 125 kHz TK4100 chip

Below you can see the reading distances when we scanned this product with different kinds of RFID readers. This is not an official test, but you will know what reading distances you may expect.
RFID Reader Reading distance
Syris RD200-LF 2,5 cm
R80D 1,5 cm
Promag PCR-330A-00  1 cm

The reading distance between the key fob and the reader is affected by many different factors and in a different environment can be different.

Technical specification for RFID key fobs with a 125 kHz TK4100 chip

Chip: TK4100
Compatible with: EM4100, EM4102, EM4200
Frequency: 125 kHz
Reading distance: up to 10 cm
Dimensions: 40 x 32 mm
Thickness: 4.5 mm
Material: ABS

If you need larger quantities or personalized key fobs, please send us an inquiry with your specification.

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