The Kingston KCS-D4000/16 module is designed for the specific purpose of plugging into a CISCO 4000-M router. It has a memory capacity of 16MB, which provides supplementary memory to the routers, which is often critical for maintaining optimal operations. The module installation process is straightforward; it is tailored to be compatible with CISCO routers so that their performance and functionality may be improved. Kingston has specialized in computer hardware and accessories for over three decades; their reputation assures users of the product-s reliability and quality.