Nauticalia

This mains powered, dual system repeller combines ultrasonic sound* transmission within the room where it is plugged in with electromagnetic pulses - particularly effective against crawling insects, such as ants, cockroaches, woodlice, silverfish etc, which are transmitted via your mains electrical circuit** right around the whole house. It also has a built in (switchable) nightlight, so is ideal for mounting in hallways etc.

*The ultrasonic element can be switched off so this version can also be used in homes with rodent pets.
 
** The electromagnetic pulses do not affect electronic appliances such as TVs or PCs.