The first 20,000 copies of the original 1973 vinyl release were encased in a sleeve depicting a Zippo lighter. The sleeve functioned as a Zippo lighter case would, opening at a side hinge to reveal the record within. However, producers soon realized that this operation would require hand-manufacture, as machinery available was not sufficient to rivet the upper and lower halves of the sleeve together. (via Catch a Fire - Wikipedia, the free encyclopedia)
