Thank you for viewing. There's a bell inside the plastic bottle cap, so it makes a sound. How about using it for a drop-in toy or building blocks? *Please be careful when small children are playing with it, and make sure they don't put it in their mouths. This is a handmade item by an amateur, so there may be some unevenness or misalignment in the thread, etc. If you understand this, please purchase it.