The Telrad has 4deg, 2deg & 0.5 deg circles which can nicely match your finder, low power eyepiece and mid power eyepiece in most 'scopes.
If you want it further from the tube just mount the base on an aluminium bracket. Extra bases can be added to other 'scopes although multiple Telrads are more convenient to avoid centreing the circles when changing 'scopes although not essential.
Batteries last for ever and the unit has variable brightness. Many astronomical resources refer to Telrad fields for locating objects and for star hopping.
Based on WWII bomb sights the Telrad was the pioneer in astronomical 1x finders in the 1980's. See also
http://www.company7.com/telrad/products/telrad.html
Here are some examples of finder charts:
http://www.custerobservatory.org/docs/messier1.pdf
http://www.utahskies.org/deepsky/cal...wellTelrad.htm
http://www.atmob.org/library/member/skymaps_jsmall.html