The ACS ACR39T-A1 card reader is a compact smart card reader compatible with SIM-sized cards, designed for portable use with USB connection to computers and compatible devices. It supports ISO 7816 smart cards of categories A, B, and C with voltages of 5 V, 3 V, and 1.8 V, as well as T=0 and T=1 protocols.

The reader features short-circuit protection, is powered directly from the USB port, and offers read/write speeds of up to 600 Kbps. It is compatible with PC/SC and CCID standards and supports Windows, Linux, macOS, Solaris, and Android. With one smart card slot and a USB Type A connector, it is suitable for authentication, electronic signatures, and other smart card applications.

The device dimensions are 49.5 x 21.5 x 9.0 mm and it weighs 8.5 g.