No battery unless it has a illuminated reticle. Red dots and holographic sights require batteries. The low power scope I'm referring to is just a plain 'ol riflescope. Just glass, no batteries.

Below is a link to the one I have (except mine is black - I'm not into camo guns). It's isn't the best by any means but has served me well thus far.

http://www.bushnell.com/general/riflescopes_trophy_73-1422ap.cfm