My entry in the Sphero make 5,000 contest. Triples the speed of Sphero in water. Printed and tested with PLA filament. Sphero will roll on flat ground with this accessory. look at instructions for more details. This was not a copy of the other water ball housings. This accessory for the sphero was drafted on the the second day of the contest.Print it twice put nubby cover on sphero put water cover on over nubby cover attach together with a zip tie through each hole. 2 bolts and nuts can also be used