Lens extension and retraction. Opening and closing of the internal blades. The above have been confirmed. There is dust on the lens, but I don't think there is any mold. ※ Please note that this is a used item, and I do not have the specialized knowledge of a camera store, so there may be oversights. Please assume that anything not mentioned has not been confirmed. We cannot provide support or warranty for any changes in condition or malfunctions after receipt. Please purchase only if you can agree to this. Returns are not accepted as this is a used item.