The SIL-X is the ultimate juggling ball. An elastic shell under filled with a very special fluid: 1/3 of its internal volume is filled with LIQUID SILICONE. The barycentre is low and the ball remains super stable on high throws and easy for foot catches and head rolling/balancing. The principle is similar to the Russian balls' although it's a very different ball. The LIQUID SILICONE, unlike any kind of sand or pellet filling, slides perfectly inside the ball so that even when the ball is thrown with a spin it doesn't wobble in the air. This special LIQUID SILICONE is totally non-toxic (normally used in the food industry as a lubricant), and therefore totally safe. This is undoubtedly the most advanced juggling ball on the market today. A truly unique PLAY invention that has conquered the hearts of thousand of jugglers for over a decade and keep making whole generations of new jugglers fall in love with SIL-X balls.