The electrodes plug into the 3.5mm (micro) jack of the GSR2 and Velcro to the fingers. They allow you to use the GSR2 without holding the unit.

The remote electrodes also help people having difficulty holding their fingers still. Or have very small hands.

You can keep it in a shirt pocket or even a purse, without holding it in your hand. The feature is also useful during sports, such as riflery or golf. Or when it is preferable to monitor from your toes in order to keep both hands free.