Metolius Bomb Shelter Double Portaledge The strongest, most durable portal edge available Innovative spreader bar keeps the frame rigid and the bed tight (1-1/8" / 28.5 mm) aircraft-quality 6061-T6 tubing for maximum strength and rigidity CNC milled corner fittings for maximum strength, light weight and easy set-up Anodized poles and corner fittings keep the parts from galling and sticking for easy set-up, corrosion resistance and durability