The Inka Pen is engineered to be conveniently accessible and write in all conditions - underwater, at any altitude, in extreme temperatures, and at any angle. Its innovative and patented, multi-function design allows you to use it as a quick-use pen or a full-size fine writing instrument, and the stainless steel split ring lets you to attach it securely wherever you need it. Housed in a durable and lightweight aluminum body, the Inka pen features a replaceable pressurized ink cartridge that gives the Inka Pen its amazing ability to Write Anywhere®.