Boston Celtics Jacket Mitchell & Ness NBA Sz Small NBA Warmup New The Boston Celtics Jacket by Mitchell & Ness is an officially licensed NBA warmup jacket in size small. It features the iconic black color and the team logo of the Boston Celtics, making it a must-have for any NBA basketball fan. This stylish jacket is perfect for men who want to show their support for the team during the NBA Finals or any other time of the season.