1.non--sealing 2.self --control 3.self --priming pump Features:Property:WFB series non - sealing self - control and self - priming pump, fills ... air control valve", achieves "once - priming, life - long self - priming."4.Small vibration, low noise, flexible move, simple disassembly ... rain, fog, moisture and humid outdoors by virtue of safe three - dimensional hood; mobile cart can move the pump ...