This is not ANY kind of Radio Frequency "blocking" material. I cover my cellphone and Ipad--and there is not change in the signal bars WHATSOEVER. Another I ordered from Ebay a few months ago Blacked it perfectly. I was seeing if this would do better. This is at best FAKE!
My correction....I am using this as of Mid March. I had angrily just packed it away. It didn't exactly block cellphone signals--which is what I thought. But it seems to actually be blocking some bit of wifi frequency. I am actually surprised. No SHOCKED!! It's not 100% and I am still in testing phase, but it just might be doing something. I will update u further. I certainly will HOLD ON TO THIS!! WTF!!