Athletic Bilbao unveiled the new home and away kits for the 2008-2009 season with new sponsor Petronor.
Equally debated, is the origin of the club colours. Although their first colours were blue and white stripes, in 1910 they switched to red and white stripes. There are three schools of thought about why this occurred.
The most common theory is that they were changed out of deference to Sunderland and Southampton, cities where the original British founders were from. Another is that an Athletic member was sent to the Britain to buy a batch of blue and white tops but could not find any and returned with red and white tops instead.
Perhaps the most credible theory, however, is that red and white striped tops were the cheapest stripes to make because the same combination was used to make bed mattresses.
The left over cloth was easily converted into football shirts. Although both Athletic Bilbao and Atlético Madrid started out with blue and white stripes, the discovery of a cheaper option probably persuaded them to change. The Madrid club did it first and they became known as Los Colchoneros - the mattress makers.
Athletic are one of the few clubs who do not have the logo of an official sponsor emblazoned on their kit. However in the UEFA cup and the Copa del Rey of 2004-2005, the shirt sported the word "Euskadi" in green in exchange for hundreds of thousands of euros from the Basque Government (red, white and green are the Basque colours).
This policy will be changed for the three seasons starting on 2008, where Athletic will play with the logo of the Biscay-based Petronor oil company in exchange for over 2 million euros.