Abstract: A metal halide arc discharge lamp comprising: an arc tube containing an arc generating and sustaining medium and having first and second electrodes sealed at opposite ends thereof; an outer envelope surrounding said arc tube and having first and second terminals for electrical connection thereto; an electrical connector coupling said first electrode to said first terminal; an electrical connector coupling said second electrode to said second terminal; a heat reflecting coating on at least one end of said arc tube; a starting aid operatively associated with said arc tube; and a light transmissive shroud positioned about said arc tube on at least two sides thereof; said arc tube having a given wall thickness of about 0.5 mm and said shroud having a thickness greater than said given thickness, the ratio of said shroud wall thickness to said arc tube wall thickness being about 2.