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. When the lens is shaken, a sound can be heard from inside, and it stops just before the ∞ mark during extension and retraction. The operation is smooth from the 1.6 mark to just before the ∞ mark. Please consider this as a junk item, assuming it needs maintenance. ※ 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 checked. We cannot provide support or warranty for any changes in condition or malfunctions after receipt. Please purchase only if you can accept this. Returns are not accepted as this is a used item.