Improve Motor Skills: Adjustable Dumbbell Toy Is Perfect For Kids To Increase Their Strength And Improve Their Motor Skills. Anti Slip And Relieve Hand Pressure: Anti Slip Handle In The Middle, Foam Effectively Relieves Hand Pressure. Children Can Use Dumbbells As Toys And Fitness Equipment. Fill Sand And Water: Children Dumbbell Toy Can Be Filled With Sand Or Water To Increase Weight. Adjustable And Colorful Dumbbell Set.