The maximum range of action of a micro-espion depends on several factors, including the type of micro-espion, transmission power and surrounding obstacles. For example, wireless micro-espions can have a range of up to 100 metres or more in a free field, but this range can be reduced by obstacles such as walls or metal objects. Wired microspions generally have a more limited scope, as they are connected to an external device. It is important to read the product specifications to know the maximum range before buying it. It is also important to respect local privacy and surveillance laws.