Scubapro Surface Marker Buoys These new professional grade surface marker buoys feature a double inflation system with an open bottom and duck beak valve as well as a metal inflator. The buoy is constructed of durable 210D nylon with HF welded seams. There’s a stainless D-ring and bungee loop on the lower end, with a plastic D-ring on top for a flashlight. Features: Open botom Duck Bill Valve Metal Valve for either Low Pressure hose or Oral Inflation 210D Nylon material with High Frequency Welded Seams with Reinforced Binding Tape Stainless Steel attachment D Ring Role up Bungee Loop Dump / Over Pressure Relief Valve Open end for Second Stage DV filling Overall lengths available 140cm or 180cm for greater surface visibility