Sandbags are used whenever you need extra weight to prevent tipping. You usually "bag" stands, especially when the weight is off center, such as with a heavy Scrim. They help stabilize equipment in windy situations and can counter balance Boom Arm applications. Matthews empty bags are completely sewn except for a 1" seam, left open for the user to fill and then sew closed. This can save on the shipping charges, however, the user will require a heavy duty machine to sew the sandbag closed properly.