Down River Equipment Rocket Box Sling Xtra-DutyThe Down River Rocket Box Sling XD is a heavy duty mesh sling designed to hang between the crossbars on your frame and store a 20mm Rocket Box or smaller. This Rocket Box Sling is constructed using Down River's strongest mesh material: Xtra Duty and their strongest side release buckles. These slings are made for real paddlers that often go hard on their gear. That means that they are ready for years and years of use and abuse. Length 18. 5in Width 8in