https://www.asmag.com/project/resource/index.aspx?aid=16&t=secutech-made-in-taiwan-products-and-solutions
Product Info
Clamshell RFID Card

Clamshell RFID Card

GID Technology Inc.
Region: Taiwan
Update: 03/27/2007
Key Specifications
Clamshell plastic card containing a RFID module and antenna

Mechanical Dimensions:

;Dimension (LxW): 86 mm x 54 mm

;Thickness: 1.85mm ∮ 0.1mm

Chip Type:

;Atmel series, EM series, Hitag series, I-code series, Mifare series

Electrical:

;LF operating frequency: 125kHz* ∮ 6kHz

;HF operating frequency: 13.56MHz Reader Standard (ISO/IEC 15693, ISO/IEC 14443)

Temperature:

;Storage: -25C to +75C

;Operating: -25C to +75C

Material:

;Copper wire antenna and module with ABS housing

Options:

;Code printing

Packaging:

;Delivered in shrink wrapped foil and packed in a box

Type Number:

;CS-XX (Clamshell Card, XX denotes IC)

*frequency adjustment 100kHz~150kHz

https://www.asmag.com/project/resource/index.aspx?aid=16&t=secutech-made-in-taiwan-products-and-solutions