I just got a Knysna SonicX kids ski for my 8 year old daughter. I wanted to post because there is almost nothing on the web about the ski, not even on the knysna website. We took it out for the first time this morning and it is awesome. It looks fast and sleek. The quality of construction and fittings seem on par with modern adults skis. The size seems perfect. It is listed as 415x47 cm and 12 kg. The weight range is listed as 30-60 kg. My daughter who is 134 cm (53”) sits with her leg length in the middle of the foot board. I see the age range listed as 5-14; my 5 yr old son who is 112 cm (44”) can just touch the footboard in shortest position but only if he makes his legs completely straight. The water line looks appropriate on flat water, in contrast to the knysna guppie and jester skis which tend to sit with a fair amount of bow out of the water. My daughter is a few kg under the 30 kg minimum, and primary stability was a touch wobbly her first time in a ski, which seems perfect to me; it is not barge stable. She never came close to tipping on flat water, and seemed comfortable cruising around right away. The boat she has been using until now is a 6 foot rotomolded sit on top and she really noticed the speed. Turning radius is small of course. Bucket seems about right. Hump is low. Cockpit rim is wide and flat making remount painless and my daughter figured it out pretty quick. There are 2 venturis with bullets.
In summary this is a great option in a dedicated kids ski, and as far as I can tell it is the shortest kids ski on the market. I got mine from Bruce Gipson at Venture Sport in Florida.
Current Skis: Nelo Vanquish AIR, Epic V10g4, NK 670 double, Epic v8 double g2, Think ion g3, NK exrcize, Carbonology Feather, Think Jet, Knysna Sonic X
Former Skis: Epic v10g3, Kai Waa Vega, Epic V12 g2, Epic V12 g1, Epic v10 double, Nelo 550 g2, Fenn Elite S, Custom Kayaks Synergy