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RFID key fobs with an EM4200 125 kHz chip
(Product ID: 1551)

Do you need identification key fobs with a 125 kHz RFID chip? We offer high quality RFID key fobs with the very popular chip, EM4200, which is an original EM chip (Microelectronic-Marin) and performs better than its competitors.

The EM4200 chip is read-only, it operates on a frequency of 125 kHz, and is backward compatible with the company’s previous chips, EM4100 and EM4102. It contains a read-only identification number, which is programmed with a laser during its manufacturing process and cannot be changed.

The RFID key fobs with 125 kHz chip EM4200 work with standard 125 kHz readers and deliver the farthest reading distances. They are used for access control and other identification purposes.
Key fobs with a standard housing contain a chip and antenna inside a pre-manufactured housing. There are more than 30 different housings available, but for products in stock we selected the most common tear shape ABS housing measuring 40 x 32 x 4.5 mm. They are available in multiple colors (blue, gray, black, green, red, orange, and yellow).

If you need key fobs with print or other customization, please send us an inquiry.
Price/item: 1,23 EUR (with vat 1,50 EUR)
Status: In stock
Dispatching time: 1-3 days

Keyfobs Colour:


Product ID: 1551


123,00 EUR

Total with vat:
150,06 EUR
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Do you need print or other specific requirements?
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Quantity Price/pcs
≥ 1 1,40 EUR
≥ 10 1,37 EUR
≥ 25 1,33 EUR
≥ 50 1,30 EUR
≥ 75 1,26 EUR
≥ 100 1,23 EUR
≥ 150 1,12 EUR
≥ 200 1,05 EUR
≥ 300 0,95 EUR
≥ 500 0,84 EUR


RFID Key fobs are RFID transponders in the form of a keychain and are convenient to use for people identification in many applications. The most important parts of a RFID key fob are the contactless chip and antenna, and the two can be built in different kinds of housing.

There is a large supply of RFID key fobs on the market, and although the key fobs are seemingly the same, there can be very big differences between them. Some web shops sell key fobs at incredibly low prices, but they can only be obtained at the expense of lower quality RFID chips and antennas and questionable quality control. This causes the received key fobs to operate at a very short distance from the reader, quickly stop working, or contain a different chip from the one specified in their technical description.

When ordering key fobs, it is especially important to select the proper chip. Do not select key fobs by their look. We typically use the same kind of housing with many different chips even though they look the same. Please note that there can be a big difference in the way they work. 

The RFID key fobs with 125 kHz chip EM4200 are made of common tear shape ABS housing measuring 40 x 32 x 4.5 mm and contain an EM chip EM4200.

The EM4200 chip was designed to replace the chips EM4100, EM4102, EM4005, EM4105, and it works perfectly even with readers designed for its competitor’s 125 kHz chip TK4100.

The key fobs are available in multiple colors. 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. We can produce key fobs with a printed chip ID code, and 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. For 125 kHz chips, the usual reading format is 10-digit decimal number (8H-> 10D conversion).

Reading test for RFID key fobs with 125 kHz chip EM4200 

The reading distance between the key fob and the reader is affected by many different factors, like the size of the antennas and quality of the chips, the interferences of metal, and electromagnetic signals, etc.

We tested the EM4200 key fobs with different kinds of readers and measured the reading distances. This is not an official test, and was made to inform you what reading distances you may expect with your application.

Below are the distances we measured with our test:
ID  RFID reader  Reading distance
1378 Syris RD200-LF 5,5, cm
1539 125 kHz RFID reader R80D 3,5 cm
1329 Promag PCR-330A-00 125 kHz RFID Card Reader 8 cm

Technical specification

Manufacturer: EM Microelectronic-Marin
Chip: EM4200
Compatible with: EM4100, EM4102, TK4100, EM4005, EM4105
Frequency: 125 kHz
Reading distance: up to 9 cm (depending on reader)
Dimensions: 40 x 32 mm
Thickness: 4.5 mm
Material: ABS
Printing options: upon request

If you need customized key fobs, please send us an inquiry.

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