1. HIGH QUALITY FLAME ALARM This electric photoresistor eye features plastic and metal construction specifically designed for burner applications. The highly sensitive photocell provides reliable flame detection performance for consistent operation in various heating systems. 2. COMPACT DESIGN With a convenient size of 5cm, this flame detector fits perfectly into standard burner systems without extensive modifications. The compact form factor allows installation in tight spaces while maintaining optimal detection capabilities. 3. EASY INSTALLATION This QRB1 flame detector is designed for hassle setup with minimal tools. Simply connect to your existing burner system by following standard wiring protocols to quickly improve the flame monitoring functions of your equipment. 4. Wide application: for residential and commercial heating systems, industrial burners and various combustion monitoring equipment. This photocell provides consistent flame detection across different device models and heating applications.