Same deal at 7dayshop but don't know if it has free delivery like Amazon.
Double Layer disc, with a Printable matt silver surface. Verbatim Double Layer Discs provide a massive 8.5GB (2.6 for 8cm products) storage capacity. The double layer of recording has been made possible by the creation of a new substrate layer that sits in between each recording layer, that allows the laser **** record on both layers. Once the first layer has been recorded, the laser re-focused to record on the second layer.