Replacement button for [popular interlocking brick toy brand whose name I am not allowed to include] Mindstorm EV3 touch sensor. This replaces the original push button, in case you lose or break that part. Please note, if you lost or broke this part, you likely also lost the spring. You will need a small spring that is just wide enough to fit around this button's center pin, but narrow enough to fit inside the sensor's opening, and not very stiff.