Official AC Siena jacket from the 2004/2005 season, produced by technical sponsor Lotto. The jacket is black with white inserts along the sleeves and features several sponsor logos. The chest displays the AC Siena crest, alongside the main sponsor Monte dei Paschi di Siena and De Luca Group Italy. The Lotto logo is visible on the chest and sleeves. On the back, the large Lotto logo and De Luca Group Italy text stand out. This jacket was used by players during training and official team travel.

In the 2004/2005 season, Siena, under the management of Luigi De Canio, secured their Serie A status with solid performances, particularly in the final weeks of the campaign.