You mean 1/48 Perforated Steel Planking (AKA PSP or Marsden Matting)?
Never heard of it. 
(These came from www.radubstore.com & www.bnamodelworld.com — there must be dozens of other sources.)
The Marston Mat was developed during World War II and was widely used in every theater of operations. Though rigid enough to bridge over small surface inqualities of the ground, it was used to best effect on stabilized subgrade. This combination provided an adequate semi-permanent runway. Some conception of the logistics problems of war can be gained from the fact that some 60,000 pierced steel sheets 15 inches by 10 feet are required for a 150 by 5,000 feet runway, weighing nearly 2,000 tons, requiring 35,000 cubic feet of cargo space to be shipped overseas perhaps ten or twelve thousand miles. A runway this size can could be put down in 175 hours by 100 unskilled men.
During Viet Nam, our photo analysts went nuts because they saw “USS” repeated endlessly on enemy airfields and other places where PSP had been co-oped. Eventually some more senior type told them “It dates back to WWII. It was made by United States Steel.”
Occasional factual, grammatical, or spelling variations are inherent to this thesis and should not be considered as defects, as they enhance the individuality and character of this document.