iSpring UVT11A, 11-Watt 110-Volt UV Transformer BallastCondition:* New Surplus Stock, In OEM Packaging. As Pictured.Additional Notes:* Smart Flow Sensor Switch automatically powers on/off UV light by water flow* Includes Transformer and Flow Sensor Switch. It works with 11 Watt UV Lamp* The kit is part of iSpring UVF11A but can also be used to add Smart Flow Sensor to other 11 watt UV filters* Resolves the issue that water gets heat up by UV light* Extends UV lamp life* Smart Flow Sensor Switch powers on/off automatically by water flowiSpring UVT11A