Unlock the power of numbers! These corresponding keys and locks give children hands-on practice with number recognition, matching and counting from 1 to 20—while building motor skills! Children simply match the number on a key to the number word or stars on a lock. If the numbers match, the key will turn—and the lock will open for instant reinforcement! Set includes 20 locks and 20 matching keys; locks measure 3 1/4" tall.