The Ultimate ORIGINAL Sensory Ball Collection: Colorful knobby balls for fun & therapy.Includes two 7"round: One 7" seethrough and 1 opaque, and two 4" round: 1 seethrough and 1 opaque.Made with the same high quality features that made it the gold standard, including thick walls and a nonremovable inflation/deflation receptacle (basketball pin type) creating long lasting fun and therapeutic toys.