These sleeves/pouches are a really handy tool for managing work permits. SDSs, etc., while making them highly visible. In my facilities, we used contractor work permits to control entry, scope of work, and exit for our covered processes. But most contractors had to obtain additional safe work permits for their specific work. And most of those safe work permits also required us to provide the contractor crew with a hard copy of the SDS of the chemical last in the vessel/pipe/duct/etc. So it would not be unusual for a contractor to have 2-3 permits and a 3-4-page SDS. These pouches kept everything nice and tidy AND clean and dry.