I saw these a couple of months ago in MBR, then almost immediately on Lloyds' race rig. For 'needless' pimping of your ride, they are beyond parallel; the wheels weight 8g each including the ceramic bearings and run a treat no matter how foul the conditions. Thick mud, long grass, dust; these just take it in their stride, and the large slots allow any gloop and debris to escape more easily.
I'm running these on both my Strike MTB and my Racelight road bike, the wheels run silently in all gears on both bikes. The only downside is a slightly heavier lever action when changing gear, due to no allowance for side play in the upper wheel (Shimano upper wheels have slight play to ease changes). Hence the 'four-star' rating, not 5. Otherwise heavily recommended.
Retailers/manufacturers' website :-
http://www.kcnc.com.tw/Web/NewWeb/mtb.htm
