This puzzle is listed on several websites with different names. Also the German name "Drehholz" or "Wooden Screwball", "Wooden Egg" or even "Sortospherial" are used. So it is more complicated to find the right name than to solve the puzzle. My version has four rings with eight wooden balls in the colours light/medium/dark brown and red. Target is to have one colour for each ring only. Top and bottom are fixed, only the middle layer with the height of one ball can be turned. Because the horizontal ring diameter and the distances between each ring are the same, not only 90 degree, but also 45 degree turns are valid, which allows a higher number of permutations. Nevertheless the puzzle belongs to the trivial category to solve.
Size: diameter 8cm, 6.5cm height. Flat on top and bottom, other rounded variants exist.