Their ability of the products to keep you grounded last only for few weeks or at most months. I bought couple of sheets and a grounding mat + body voltage meter and plug tester. In the beginning the sheet and the mat grounded just fine. I tested them both. Now after about 6 months I tested again and both the sheet and the mat had totally lost their ability to ground you. Wrote the feedback to the Aarding about this problem and Ludo's only suggestion or 'compensation' was that I would get 25% off from my next purchase. Who wants to buy more stuff that does not work after few weeks. I washed the sheets with non bleach detergent (no peroxides), with delicates program, never heat dried, never ironed, always slow dried on extended drying stand. So had taken good care of the sheet all the time. The mat has never even been washed or such. I tested too that the body voltage meter worked fine (tried against radiator) and the mat's and sheet's cables worked fine too. So the problem is with the actual products. Even Ludo admitted that the life span for sheets is maximum 1-2 years and mats should have no problem at all. In practise they both work for a lot shorter time. The sheets are way too expensive to be able to ground you only for few weeks or months. I would suggest that you buy some other provider or those cheap 'Chinece' alternatives if both are able to ground you only for couple of months - the chinese ones are at least much cheaper to renew.