Unique triple cemented lens reduce the distortion and spherical aberration of light ; very suitable for the focus of collimated beams Easy to use, accurate collimation in a few minutes provide a more clearer image; just watch the collimator from the mirror end of the scope and adjust the screws This collimation has built-in battery and supports 7 levels of brightness adjustment of laser,suit for different light conditions. Eyepiece Collimator.Power saving design, low consumption and durable for long time use,Suitable for Newtonian, Marca telescopes Easy to target.It is very easy to simply look at the target and adjust the telescope until the red dot is centered. No need to keep looking at the cap in the telescope's eyepiece.