The reflex lens can folds flat against the optic body when not in use and the folding lens can be quickly deployed with the press of the ambidextrous side levers. The Solar cells are mounted on top of the reflex sight and will power the red dot whenever there is sufficient sun light on the solar cells. The red dot automatically turns on, when there is sufficient sun light. The SPD FlipDot can also be powered by the onboard CR2032 battery. The battery should be used when there isn&';t enough sun light, when using the optics indoors, or when using the optic at night. A red LED indicator on top of the optic by the solar cells will turn on when the red dot is powered by the battery. SPD Solar FlipDot reflex optic features a folding reflex lens assembly, the red dot can be operated via two different power sources (via solar cells or battery), and a modular KPM mounting system (KeyMod/ Picatinny/ M-LOK).table.productattributes, .productattributes td { border-bottom: 1px solid #ddd; border-collapse: collapse; padding: 2px; text-align: left; }