DAILY RFID CO., LIMITED is the professional provider of 125KHz(Low Frequency) RFID Key Tags, RFID Key Fobs, RFID Key Rings with the chip TK4100 in china.
In this month, DAILY RFID gives a promotion on TK4100 RFID Key Fobs, you can check the website for more special price information:

RFID Key Tag-02 USD$0.17
Product Details:
1)Type: Contactless Read & Write
2)Operating Frequency: 125KHz or 13.56MHz
3)Compliance
. IC Available at 125KHz nominal:
EM4100, Hitag-1, Hitag- 2, Hitag-S, TK4100
. IC Available at 13.56MHz nominal:
Mifare-One S50, Mifare-One S70, I-CODE, Ti 256, INSIDE 2K
4)Material: ABS
5)Physical Size: 3.5cm*2.8cm
Thickness: 6.4mm
Standard Color: Blue or other colors
6)Printing: Printable with silkscreen (no more than 2 colors)
A customized logo can be printed on the tag
7)Operating Temperature: -10℃ to +50℃
8)Storage Temperature: -20℃ to +70℃
9) Packing: 100PCS/BOX 2000PCS/CARTON
Carton Size: 50× 24× 28CM