Sweeping is by all means not foolproof. 

Advanced bugs can be remotely operated to switch on and off, and some may even rapidly switch frequencies according to a predetermined pattern in order to make locating with sweepers more difficult. 

A bug that has run out of power may not show up during a sweep, which means that the sweeper will not be alerted to the surveillance. 

Also, some devices have no active parts, 

if there is no signal to detect with our range of equipment then we rely on visual search.

Rest assured if you are been monitored with any device we will find it .

This is what we do, and have been doing it for 30 years .

Once again If you think your security has been compromised, do not call or message us from the suspect locations or devices!