5 tread All GRP Glass Fibre Swingback Steps for spark risk sites that demand minimal metal content equipment. All glass fibre steps are the solution with robust GRP stiles & treads. Closed Height (m) 1.3. Open Height (m) 1.25 Rungs/ Treads 5 Material Glass Fibre. Usage Type Heavy Duty. Warranty 5-Year. Standard EN131. Open Depth (m) 0.98. Weight (kg) 6.5