Fiberglass tarp used for welding.Key value points:1) construction and thickness appropriate for blocking welding sparks and grinder sparks.2) construction around grommetsI use this for temporary outdoor welding walls to shield from wind and contain sparks. The tarps hang from a frame via the grommets.I_e used this for a couple of welding sessions so far and the quality is great, covering all my needs.As a bonus, I especially like the case so that it can be stored easily.Some care needs to be taken to watch for fraying (it is fiberglass) but I have not had any problems so far.I would buy this again.