Step Up Ring 40.5-49mm

Step-up rings are used when you need to mount a filter that's larger than the diameter of your lens barrel. The first number refers to the barrel size, and the second number indicates the filter size that will fit on the ring. Step-up rings are a great way to save money on filters, since instead of having to buy several different sizes of filters for your various lenses, you can buy just one large filter and several inexpensive step-up rings instead. A must for the photographer on a budget."