BT Wholesale provides wholesale ADSL broadband products to most of the UK’s ISPs. ADSL MAX lines are enhanced versions of the standard IPStream / Datastream ADSL products and use Rate-Adaptive (RA) technology to dynamically find the best ‘stable’ speed for your line. It is capable of offering speeds up to 8Mbps download and 448Kbps (800Kbps business) upload, though most will receive far less.

See our broadband page for a more detailed explanation:
http://www.ispreview.co.uk/broadband.shtml#3