The Tethys prototype consists of a white cardboard box that has a slit cut into the front panel. The box does not have a bottom panel and the back panel has a printed white sticker with an image of water. The top of the white cardboard box has a square white sticker with a printed logo on the top left corner. TETHYS is handwritten in gold pen underneath the sticker. There is a printed image of a computer board adhered to the right top of the box; a blue star-shape drawn directly underneath it. There is an Arduino Yún board on the center top of the base. The board is blue with various metal elements. There are orange, yellow, and green wires attached from the computer board to the cardboard box top.
Originally, the cardboard models did not work and never were meant to work but rather help Gitanjali understand what a mobile device could look like. With the help of Denver Water and Dr. Selene Hernandez-Ruiz, Gitanjali turned her cardboard model into a working prototype.
Gitanjali Rao is a resident of Lone Tree, Colorado and at the age of 11 won the Discovery Education 3M Young Scientist award in 2017. Inspired by the Flint, Michigan water crisis, Gitanjali created Tethys, a water-testing device that is portable and can quickly and cheaply provides users whether or not there is a dangerous presence. Rao was named one of Forbes 30 Under 30 in 2019.