A rubber composition for a hollow ball includes a base rubber and an inorganic filler. A weight reduction rate TGA.sub.650 from room temperature to 650° C. and a weight reduction rate TGA.sub.850 from room temperature to 850° C. of the rubber composition are measured under an air atmosphere by thermogravimetry conforming to JIS K0129. The weight reduction rate TGA.sub.650 of the rubber composition is not less than 63% and not greater than 99%. A difference (TGA.sub.850−TGA.sub.650) between the weight reduction rates TGA.sub.850 and TGA.sub.650 of the rubber composition is not less than 0% and not greater than 7%. A hollow ball 2 includes a hollow core 4 formed from the rubber composition.

A filling device may be used to fill a ball or other inflatable item from a water source such as a hose. A filling device may include an adapter having a cylindrical body with a hollow threaded interior, one closed end and one open end. A filling coupler is coupled to the one closed end of the cylindrical body. The one closed end of the cylindrical body has an opening formed therethrough and the filling coupler is coupled to the one closed end covering the opening. The filling coupler has a hollow threaded interior in fluid communication with the opening. A tip may be removably coupled to the filling coupler. The tip may be a ball inflation needle, a water balloon filling tip or the like.

A rubber composition for a hollow ball includes a base rubber and an inorganic filler. A weight reduction rate TGA.sub.650 from room temperature to 650 C. and a weight reduction rate TGA.sub.850 from room temperature to 850 C. of the rubber composition are measured under an air atmosphere by thermogravimetry conforming to JIS K0129. The weight reduction rate TGA.sub.650 of the rubber composition is not less than 63% and not greater than 99%. A difference (TGA.sub.850TGA.sub.650) between the weight reduction rates TGA.sub.850 and TGA.sub.650 of the rubber composition is not less than 0% and not greater than 7%. A hollow ball 2 includes a hollow core 4 formed from the rubber composition.

An illuminated water toy may be used to play games or to practice diving in the water. An illuminated water toy may include a body containing a light emitting device. The light emitting device having a first circuit board, a light emitting element coupled to the first circuit board and a battery housing coupled to the light emitting device. A second circuit board is coupled to the battery housing. Four conductors are coupled to the second circuit board with two of the four conductors being coupled to the light emitting device. Another two of the four conductors are coupled to two water contacts, wherein the two water contacts are located on an outside of the illuminated water toy, and wherein on exposure to water, the two water contacts are electrically connected causing the light emitting element to be illuminated.

A filling device may be used to fill a ball or other inflatable item from a water source such as a hose. A filling device may include an adapter having a cylindrical body with a hollow threaded interior, one closed end and one open end. A filling coupler is coupled to the one closed end of the cylindrical body. The one closed end of the cylindrical body has an opening formed therethrough and the filling coupler is coupled to the one closed end covering the opening. The filling coupler has a hollow threaded interior in fluid communication with the opening. A tip may be removably coupled to the filling coupler. The tip may be a ball inflation needle, a water balloon filling tip or the like.