A monstrously cute vehicle for babies 6 months+ to rattle & roll around! The center roller wheel underneath lets the vehicle wobble & roll along Rattle beads within the roller wheel make fun sounds as the vehicle zooms around Sized just right for little hands to grasp & push Collect additional Mini Monster Trucks for more zooming fun! (Each sold separately and subject to availability) Let's roll, baby! With a center roller wheel filled with rattle beads underneath, the Fisher-Price Mini Monster Truck gets wibbly-wobbly as your little monster sends it zooming around. Bring this vehicle to the Monster Trucks Racing Ramp for ferociously fun racing action! (Racing ramp sold separately and subject to availability.) Where development comes into play -- Fine Motor: The vehicle is sized just right for your baby's hands to grasp, strengthening dexterity. Gross Motor: The truck's wobbly roller wheel encourages your baby to push the vehicle along as they crawl here, there, and everywhere.