The Quad weight sensor precisely monitors shelf load to detect real-time product interactions in retail displays. With high measurement accuracy, it instantly identifies when a product is lifted or returned, triggering immediate API messages to enable responsive content, analytics, or system actions. In displays featuring multiple product types, the sensor intelligently distinguishes which item has been picked up by analyzing weight variations, even when differences between products are minimal. The Quad type supports large shelves with mounting points at all four corners.