Wireless smart water shutoff valve that closes the main water supply in 7 seconds the moment a leak is detected — automatically, without anyone home, without anyone touching a tap. WaterStop combines a quarter-turn ball valve with a high-torque electric actuator on the supply line, and when paired with Ajax LeaksProtect detectors (or a compatible third-party leak sensor), the hub triggers the actuator the instant water is sensed at the source — turning a flood that could ruin floors, ceilings, and stock into a controlled stop. Beyond emergency response, WaterStop runs scheduled scenarios: shut off automatically when the alarm system is armed (no one home → no water supply → no risk), at a fixed time each night, or linked to other devices in the Ajax ecosystem. It pairs with the Ajax Hub 2 over the encrypted Jeweller radio protocol at distances up to 1,000m line-of-sight, runs on permanent 100-230V AC power, and includes a manual override lever for outage scenarios plus a periodic anti-jam test cycle that keeps the valve from seizing during long idle periods. Available in 1/2″, 3/4″, and 1″ BSP threading for hot and cold lines, IP44 rated, status readable from anywhere via the Ajax app. Ideal for villas, apartments, hotels, offices, retail spaces, and server rooms — anywhere a single overnight leak can cost more than the entire Ajax system.