This filter will fit a telescope with an optical tube end (opposite the eyepiece) outside diameter of 5 5/8"(143mm) to 5 7/8"(149mm). It will specifically fit the Meade: ETX 125, 114EQ, & DS2114 ATS. This is a safe full aperture glass solar filter. This means that it allows the most light possible into the telescope because it allows the full aperture of your telescope to be viewed. The full aperture allows the best possible daytime viewing when there is minimal atmospheric turbulence. The aperture is made with metal coated scratch free glass that produces a natural yellow orange image of the sun. This is a high resolution glass filter that can be used for photography and direct view of the sun. This filter is new in the box in plastic. The filter box is foam lined for protection and shock absorption during handling. It is durable enough to store the filter while not in use. Included with this filter are instructions for use and care. Specifications: The Outer Cell Inside Diameter is 6"(152mm) and the Clear Aperture Diameter is 5"(127mm).