The device is pressed with the light surface to the skin, and only when this area is positioned properly with the skin sensor, the light pulse to be issued. Too dark skin it can happen that the device refuses as this can then be harmful. It is also recommended that the equipment really impose good because it lets the outline later see where you have been, and where not. Because twice should not be confronted in treatment with the light one and the same place.
By treating yourself you realize nothing. Only a small electronic audible bang leaves a first somewhat cringe but rather as a shock than anything feeling.
There is another method (slipper) for the treatment of larger areas (eg legs) where you push the device to the light head over the skin surface, and the device will automatically continuously impulses from.
So simple it sounds all the more patient you have a however. For a visible success is achieved only through weeks or months of treatment. Different skin tones and hair colors must be respected. These range from good to not treatable, and is stated in the description in the form of a table. As a rule of thumb it can be stated, the lighter the hair and the darker the skin, the worse the success.
The device operates with a replaceable cartridge containing up to 100,000 pulses of light. According to the description of the manufacturer, but these are sufficient for up to 26 years Ganzkörperenthaarung. And which appliance to use already 26 years? Therefore, you should not make any big ideas about a replacement of this component.
The important thing is that one does not expect too quick results and the various safety instructions followed to prevent damage to the skin occurs.