Tiffen MegaPlus 49mm-55mm Adapter Ring;

Step rings allow the attachment of different size filters and accessories to a lens. Step rings are available in step up and step down rings. To determine which type of ring you need, always start with the filter size that fits on your lens and then compare it to the filter size you want to adapt. If the filter size of the lens is smaller than the filter size that you want to adapt, then a Step Up ring is needed.