The 63355 Calibrated Source Lamp is a 200 Watt Quartz Tungsten Halogen (QTH) light source with a 7.0 x 3.6 mm diameter filament. QTH lamps are known for their excellent stability in emitting high intensity visible to IR wavelength output, with minimum UV emission. A calibration certificate is supplied with this lamp confirming NIST-traceable standards over the 300-2400 nm wavelength calibration range. This lamp is intended for open air mounting instead of enclosed lamp housing operation.  Lamp replacement is typically recommended after 100 hours of use to maintain certificate value uncertainties.