The present invention concerns a device and a method, for placing and securing sensors/electrodes on the head of an individual. Said device/method optimizes signal information and avoids some of the problems connected to the devices and methods in the prior art. The device comprises a rigid and fluid-proof outer layer (4), an elastic and fluid-proof inner layer (3) with placement points for sensors or electrodes (1,5), and a middle layer comprising a fluid between inner and outer layers. The device also comprises means (7,9) for regulating the pressure of said fluid. Inner and outer layers are only directly joined along the circumference of the inner layer.
