The Telrad is a favorite of amateur astronomers.
The main selling points are a real field of view with no magnification and no inversion, and the only graduated reticle image with 1/2°, 2° and 4° increments which aids star hopping activities. The image is focused at apparent infinity that in use gives the appearance of actually being in the star field. The reticle is also dimmable to allow use in both light polluted and dark sky conditions.
Most people starting out with the Telrad Reflex Sight find it so easy to use that they use it exclusively in lieu of a finder scope.
Operates on two AA batteries, not included.