These ferrites are high quality general purpose ferrites, and are highly effective at lowering the type of Dirty Electricity that can be found on house mains, produced by electronic goods. They are appropriate for fitting to cables that may be carrying Dirty Electricity close to areas where large amounts of time is spent, such as bedside lamp leads or alarm clock leads. One size fits all up to 7mm diameter cable. Very thin wires can be wound round in a loop so that two lengths pass through the core which will increase the screening effect. If the diameter of the lighting cable is thin, then the hole in the ferrite can be made smaller with cling film or any other suitable non-conductive material.
These ferrites are also suitable for clipping onto telephone lines if an ADSL filter cannot be fitted for any reason.