The Pentair RE2043600 is a Fuse Kit compatible with Rheos™ 1200/1600/2000/2400 Boiler and Water Heaters. It is 2 A, and a 5/Pack. Rheos boiler/water heater technology uses precise modulation control that sense the existing conditions and automatically adjusts the boiler performance to meet the required heating load. At 86% combustion efficiency, the Rheos can greatly cut fuel costs compared to older boiler installations. It is a genuine Pentair product.