I Used a sound proofing forum as they were the cheapest supplier for the products (most suppliers seem to flog the same or very similar stuff). Saved quite a bit compared with places like customaudio/domesticsoundproofing/soundstop etc... , but the after sales help was a bit slow, I phoned them and they said they would phone straight back with the technical details, but I had to ring them the next morning to remind them to get the details.