"Two colorful sensory ball sizes for twice the play potential! This set includes two 7"" balls, one see-through and one opaque, and two 4"" balls, one see-through and one opaque in an assortment of four primary colors to capture your child's interest. You will find they are well constructed of highly durable materials, including thick walls and a non-removable inflation/deflation receptacle (basketball pin type). These balls can be used solely for recreation, but can also be used for therapeutic purposes. Rmended for ages 6 months and above. Gender: unisex."