In summary, wireless transmission of power has numerous advantages. For example, it makes fault-prone plug contacts redundant. Devices can be built into housings that are protected against moisture ingress. Users also do not have to go to the trouble of plugging in cables. Most wireless power transmission applications lie in the field of charging batteries in portable devices. There are a few established standards in this field; however, there are many applications for which no standard is necessary. Hence, individually-optimized power transmission can be used.