The QRB... are designed for the supervision of yellow-burning oil flames in connection with burner controls type LAL..., LME7..., LMO..., LMV... and LOA...

They are suited for frontal or lateral (90 degree angle) illumination.

The maximum spectral sensitivity of the QRB... is about 600 nm, thus giving full consideration to the maximum level of visible light radiation of yellow-burning oil flames. Since the QRB... also acquires certain parts of the radiation spectrum of other lightsources (boiler room lighting, solar radiation, etc.), the standard regulations regarding safety in connection with extraneous light still apply.