Finderscopes are monoculars attached atop or aside of a telescope, with lower magnification and a wider viewing field to help hunt down the general neighborhood of the object of interest.
This 7x50 Illuminated Finderscope, like the entire lineup from Vixen, uses a bracket that attaches to a matching shoe on the telescope. With its larger exit pupil, it is both brighter and wider of field than Vixen's 10x50mm version, though there will be devotees to both varietals because some observers prefer a bit more magnification.
Additionally, if you are an "experienced" enough observer to have a maximum pupil diameter of ~5.0mm, you will not observe any more brightness with the 7x50 than the 10x50.
This model features a floating illumination 'dot' in the center of its field of view, to help align the finderscope to the main scope.