The AcuRite Portable Lightning Detector provides lightning protection with warnings for cloud-to-ground, cloud-to-cloud and intra-cloud lightning strikes within a 25 mile range. The lightning tracker notifies you with a loud alarm, flashing red LED light and text message on the backlit display when storms or lightning are within range. Pocket-sized with no-slip clip for portability. The lightning detector features enhanced interference rejection capabilities to prevent false lightning detection. Outdoor and indoor operation modes.