The Philips MHN-TD 150W lamp quartz discharge tube contains high-pressure mercury and a mixture of dysprosium, holmium and thallium halides (MHN-TD), or tin iodide (MHW-TD), with sodium thallium added for colour correction and arc stabilization.
It's a double-ended lamp housed in a tubular clear UV-block quartz evacuated outer envelope.
All types are UV-block for reduced health and fading risks.