Humiditrak sensors are supplied with two pieces of Velcro for quick and easy mounting to your instrument or case. To mount the sensor, simply take two pieces of the same side of the Velcro and place one on the raised square on the back of your sensor and the other directly below it in the center of the battery door. Next, remove the plastic backing from the other half of each piece of Velcro and mount it wherever your to your instrument or case. Alternatively, you can use the Velcro to attach the sensor to the metal clip provided and then clip the sensor inside your case.