The ACR100 SIMFlash is a USB plug-and-play smart card reader that supports various card types including SIM and memory cards with customizable storage options. It features a built-in 1GB flash drive capable of secure transactions and digital signatures, with compliance to PC/SC, CCID, and HID standards. Additionally, it supports both contact and contactless operations, making it versatile for applications in telecommunications, banking, and secure data storage.