eely

adjective [原级]似鳗的；易滑脱的；滑头滑脑的

The outer-body diameter of the plunger is cut just under production tubing drift to provide the maximum seal while the plunger moves fr eely.
当柱塞自由移动时，柱塞的外体直径刚好能够满足生产油管内径密封需求，提供最大的密封保障。