Nanotechnology
Most listening devices work by transmitting the sounds they pick up on radio waves. This would suggest that the transmissions could be picked up and recorded well away from the scene. This would indeed be possible if the signals were as strong as a normal radio transmission, but a bug sending out a signal as strong as this would be extremely easily detectable. To remain hidden the signal must be much weaker, so the listening post must be situated as close as possible to the transmitter. This is why vans are often used to park close to the bugs. These vans will often also be equipped with concealed cameras, so the spies inside can keep a really close eye on the whole area.

Lock Picking
For every different type of lock in existence there has to be a specialised way of opening it. The most common type of lock is the pin tumbler. Inside one of these locks is a range of pins which must be pushed into the right position to be able to rotate and open the lock. When you look at a standard door key, you'll see that it has a range of notches along the edge. These correspond to how the pins should be positioned, any other key would position the pins wrongly, and fail to turn the lock.

A lock-picker will use a pick tool to carefully nudge each pin, one by one, into the appropriate place. It sounds simple, and the theory is very simple. However, the practice is a highly skilled technique. It takes a lot of experience and knowledge to recognise the sounds and sensations that mean the pins are gradually nudging into the right place.

Copy Camera
A copy camera is a camera specifically designed to take photographs of documents. A regular camera can be used for this purpose but it is difficult to ensure that all the writing stays in focus and legible. While a photocopier does the job perfectly well in an office, a spy working undercover would need something considerably more portable and discreet.

To copy text effectively all you need to do is ensure that the camera is correctly focussed on the document. This can be achieved by setting a fixed lens and focus in the camera. With no adjustable settings, if the camera is always held at a set distance from object results will always be consistent. To this end most copy cameras will include a device for ensuring it is positioned correctly.