The Vintage Mining CSE/SRLD Self-Contained Self-Rescurer with long duration is a unique and valuable collectible item originating from the United States. This historical device was used in mining operations and represents a significant piece of science and medicine history. Its self-contained and self-rescurer capabilities make it a rare find for collectors interested in mining artifacts and vintage technology. Its probably not reusable but its for collecting old vintage mining equipment. And this is a rare collectable to have.