Shaquille O'Neal wears one. Benji Marshall swears by them and now the Wellington Hurricanes Super Rugby team and Prime Minister John Key are sporting them.
They're the power balance band, something akin to an oversize rubber band that you wear on your wrist.
Their makers claim they improve your strength,
balance, flexibility and endurance.
And at upwards of $70, depending on which brand you buy, there seems to be a ready market of people willing to shell out to try them.
The secret, the makers say, is the "frequency infusion technology" in the little metal holograms inserted into the rubber. In layman's terms, the holograms give the bands power.
Depending on who you believe - and the internet is full of opinions on the subject - the bands boost performance or offer no benefits at all. All Black and Hurricanes' winger Hosea Gear says he wears his EKEN band for training and matches "to give me the edge out on the field".
So, in the interests of science, EKEN supplied a band for me to test the claims.
The snazzy black number with white lettering looked smart on the wrist and elicited several favourable comments. It gets a tick for style.
It's like wearing a watch but is flexible, so gets a tick for comfort.
Now to the claimed benefits.
I wore it for a week. In the day-to-day environment I didn't notice any change in any of areas the makers say should show improvement.
But as a daily jogger I thought there could be benefits to worn hip and ankle joints. No tick here. No noticeable improvements - in fact for several days I had pains running up and down my right leg which stopped when I took the band off.
The test was totally unscientific, like some of the political polls John Key will eye ahead of November's general election. He'll be hoping for better luck in the strength, flexibility and endurance stakes.
