| 摘要 |
<p>Half of the stopper projects from the discharge pipe which it blocks, easing extraction. It can be placed on all sizes of discharge of waste or rain water, straight or bent. The stopper is pref. of plastics, with a spiral channel of rubber or other material formed on it. The stopper may be of the suction type. The stopper unblocks pipes without using noxious or corrosive liquids.</p> |
