LeapFrog LeapReader Junior: Toddler Milestones Book Set (works with Tag Junior) This set of 4 board books features beloved characters that show toddlers how to approach big developmental milestones. Includes a Parent Guide full of expert insights and tips to help you and your toddler at home. Teaches social skills, feelings, routines and counting. Ages 2-3 years. Works only with Tag Junior and LeapReader Junior (sold separately).