Need a small trick to be perfect
When I received it, I was very disapointed : my cursor was erratic, impossible to be accurate.
When I looked at the light sensibility on the Wii options, I noticed that I had 4 points instead of 2 with the official bar : there was a problem...
Here's the workaround :
on the bar, you'll notice 4 LED. Hide the first and the fourth LED with a piece of paper thick enough to block the infrared.
Doing so, you'll get a perfectly working sensor bar, at a very low price !

Two AAAs not six AA batteries!
All works very nicely. A bargain for the price.
Play Asia's product spec is wrong though. They say:
"Continuous use for 72 hours using six AA size batteries"
The product actually takes just two AAA size batteries.

****comment Play-Asia: Thank you for the notification - we just corrected the specificaion****