Moeller Marine 033802-10 Aluminum Anti-Siphon Barb Anti-siphon valves, are required by Federal Law and the USCG on all permanent fuel tank installations.; Use 15 (Brass) calibrated for HP 200 & above and 30 (Aluminum) calibrated for HP below 200 HP.; Deliver Coat Guard/industry standard anti-siphon protection on all gasoline-powered boats.; Combines anti-siphon protection with a convenient hose barb design.; Specifications: 3/8" Barb; 3/8 NPT Threading; Aluminum; Calibrated for HP below 200;