Here the light source, optic & user friendliness interact / collude ideally. 3 Mono batteries take care of sufficient energy & a surprising long life on low costs. The newly developed step switch provides an extreme bright or dimmed light so that the lamp can be used in distant & close areas & also suitable for antidazzle reading. Naturally, the P17 is fully loaded with our scientifically developed Superoptic technology that sets new standards in the focussing technology worldwide.