NBA Boston Celtics 9Fifty Snapback Cap (Black/Green, One Size Fits All) by New Era. $24.99. This 2Tone 9FIFTY Snapback cap features an embroidered (raised) team logo on the front, a stitched New Era flag at wearer's left side, and a contrasting visor. The kid's 9FIFTY is styled just like the adult with a snapback closure for an adjustable fit. Interior includes branded taping and a moisture absorbing sweatband.