They can offer products at sometimes considerably lower prices, due to not necessarily having to conform to the same regulatory requirements as BT Wholesale: for example, 8 unbundled LLU pairs can deliver 10 Mbit/s over 3775 m for half the price of a similar fibre connection. In 2005, another company, Be, started offering speeds of up to 24 Mbit/s downstream and 2.5 Mbit/sec upstream using ADSL2+ with Annex M, eventually from over 1,250 UK exchanges. Be were taken over by O2's parent company Telefónica in 2007. On 1 March 2013 O2 Telefónica sold Be to Sky who have now migrated O2 and Be customers onto the somewhat slower Sky network. Exchanges continue to be upgraded, subject to demand, across the country, although at a somewhat slower pace since BT's commencement of FTTC rollout plans and near-saturation in key geographical areas. Up until the launch of "Max" services, the only ADSL packages available via BT Wholesale were known as IPstream Home 250, Home 500, Home 1000 and Home 2000 (contention ratio of 50:1); and Office 500, Office 1000, and Office 2000 (contention ratio of 20:1). The number in the product name indicates the downstream data rate in kilobits per second. The upstream data rate is up to 250 kbit/s for all products. For BT Wholesale ADSL products, users initially had to live within 3.5 kilometres of the local telephone exchange to receive ADSL, but this limit was increased thanks to rate-adaptive digital subscriber line (RADSL), although users with RADSL possibly had a reduced upstream rate, depending on the quality of their line. There are still areas that cannot receive ADSL because of technical limitations, not least of which networks in housing areas built with aluminium cable rather than copper in the 1980s and 1990s, and areas served by optical fibre (TPON), though these are slowly being serviced with copper. In September 2004, BT Wholesale removed the line-length/loss limits for 500 kbit/s ADSL, instead employing a tactic of "suck it and see" — enabling the line, then seeing if ADSL would work on it. This sometimes includes the installation of a filtered faceplate on the customer's master socket, so as to eliminate poor quality telephone extension cables inside the customer's premises which can be a source of high frequency noise.