Heavy-duty bags provide quick and easy sediment and erosion control. Some may consider gravel bags to be "old school" but in some applications, they are an excellent solution. To say that gravel bags have come along way over the years may be an overstatement but to say that they are the same now as they were on day 1 would be selling them short. At least when describing Ultra-Gravel Bags. UltraTech's bags are made from heavy-duty geotextile material with a high UV rating so they're designed for years of outdoor exposure. All Ultra-Gravel Bags are sold empty so they're easy to get onsite. Fill them with sand, gravel or other aggregates to create quick and versatile erosion control