All Darton scopes are fitted with an adjustable ocular focus. To focus your eye characteristics to the scope, giving a crystal clear picture of the reticle, carry out the following adjustment.The illumination rheostat is located on the side of the saddle. High brightness settings are recommended for daytime use when ambient light is bright, this will allow the reticle to be visible against dark backgrounds. At times of low light, such as dawn or dusk, a lower brightness setting is recommended. The lower settings may not be visible during bright daylight. Reticles are black in the off position or if the battery is defective.Scope rings are included.