The Advent is considered the best in its class for durability and stability. Stainless Steel 304 heat treated body, designed for extreme and continuous service in permanently rigged challenge courses, commercial ziplines and eco-tourism applications. This pulley has 2 points of attachment both primary and back-up. Great for commercial operators. This product is strong and reliable with sealed ball bearings & long wear alloy sheaves making it the ideal tandem pulley.