If you are watching the Celtics-Cavaliers game tonight, count how many players on the court are wearing headbands. Given that it’s a voluntary piece of gear, it will be quite an amazing number.

I haven’t gotten this confirmed but I’m betting that the Celtics will have Paul Pierce, Rajon Rondo and James Posey wearing headbands. The Cavaliers will have LeBron James, Anderson Varejao and Daniel Gibson wearing headbands (with Devin Brown on the bench). Gibson is hurt and out for tonight's game 6.

In fact, the headband has become such a part of LeBron James’ wardrobe that Brian Windhorst, the Akron Beacon Journal team beat writer told me, “You take LeBron’s headband off and he looks like he’s naked.”

Cliff Robinson was the only player to wear the headband for years, but about five years ago--probably as much for fashion as for mopping up sweat--the headband was legitimized.

Aside from the Bulls, where former coach Scott Skiles banned headbands (with a Ben Wallace exception) and his predecessor Tim Floyd called headband-wearers “soft,” and the Jazz, where coach Jerry Sloan has always had a permanent ban, it’s common to see three or four players on a team wearing them.

All that has translated into a bump in sales for headbands. Headband sales are up 38 percent from last year at the NBA Store in Manhattan and on NBAstore.com, according to league spokesperson Kristin Conte.

Conte also reports that the best non-apparel item being sold by the league are shooting sleeves. I honestly couldn’t imagine many kids buying these, but because they are hot, I’ve now decided to come to work everyday now in a headband and a shooting sleeve.

CNBC.com Darren Rovell wearing the shooting sleeve and headband.

CNBC.com Darren Rovell wearing the shooting sleeve and headband

Questions?  Comments?