introduced a grey strip which had been specifically designed to look good when worn with jeans, but abandoned it halfway through a match after manager Alex Ferguson claimed that the reason why his team was losing 3–0 was that the players could not see each other on the pitch. United switched to different colours for the second half and scored one goal without reply. The leading leagues also introduced squad numbers, whereby each player is allocated a specific number for the duration of a season. A brief fad arose for players celebrating goals by lifting or completely removing their shirts to reveal political, religious or personal slogans printed on undershirts. This led to a ruling from the International Football Association Board in 2002 that undershirts must not contain slogans or logos; since 2004 it has been a bookable offence for players to remove their shirts. The market for replica shirts has grown enormously, with the revenue generated for leading clubs and the frequency with which they change designs coming under increased scrutiny, especially in the United Kingdom, where the market for replicas is worth in excess of £200m. Several clubs have been accused of price fixing, and in 2003 Manchester United were fined £1.65m by the Office of Fair Trading. The high prices charged for replicas have also led to many fans buying fake shirts which are imported from countries such as Thailand and Malaysia. The chance for fans to purchase a shirt bearing the name and number of a star player can lead to significant revenue for a club. In the first six months after David Beckham's transfer to Real Madrid the club sold more than one million shirts bearing his name. A market has also developed for shirts worn by players during significant matches, which are sold as collector's items. The shirt worn by Pelé in the 1970 FIFA World Cup Final sold at auction for over £150,000 in 2002. A number of advances in kit design have taken place since 2000, with varying degrees of success. In 2002 the Cameroon national team competed in the African Cup of Nations in Mali wearing shirts with no sleeves, but FIFA later ruled that such garments were not considered to be shirts and therefore were not permitted. Manufacturers Puma AG initially added "invisible" black sleeves to comply with the ruling, but later supplied the team with new one-piece singlet-style tops.