... 1.non--sealing 2.self --control 3.self --priming pump Features:Property:WFB series non - sealing self - control and self - priming pump, ... air control valve", achieves "once - priming, life - long self - priming."4.Small vibration, low noise, flexible move, simple ... G, PP, BXG in "Material Symbol" signifies steel, reinforced polypropylene and stainless steel.(2):Examples for type significancestable1: