1.non--sealing 2.self --control 3.self --priming pump Features:Property:WFB series non - sealing self - control and self - priming pump, fills ... self - suction performance, in particular, the adoption of "electric air control valve", achieves "once - priming, life - long self - priming."4. ... , no need to fix anchor.5.Blessed with excellent self - control, can match to hi - tech and hi - auto systems ...