Valve, Chem-Vac, Glass Barrel Only, Without Sidearm, 0-8mm Bore, 19mm OD Barrel. Glass barrel only, without sidearm, for all CHEM-VAC valves. Heavy duty rounded coarse thread and precision formed tapered seat. PLEASE NOTE: THE 0-20mm BORE SIZE VALVE IS Chemglass's PREVIOUS STYLE CG-500 SERIES VALVE WITH COARSE THREAD.