This heavy solid sterling silver charm is an inner tube that says tubing on it. It looks as good on the front as it does on the front. Growing up in Texas I have inner tubed in the Guadelupe River, Comal River, Frio River, and Nueces River. It is a great memento! It is 13 mm tall and 19 mm wide. The finish and casting differs with each charm since it is hand cast by a specialty manufacturer here in Texas.