An inspection lens, including a lens tube having a central longitudinal axis and a plurality of axially aligned optical elements, including an outermost element. A sheath surrounding the lens tube and defining there between an annular air flow channel. The sheath has a diversion nozzle at a distal end, terminating in a lens tip. The diversion nozzle is configured to divert the air flow in the annular channel inward toward the longitudinal axis and at a slight reverse angle of between 0-18 degrees relative to a plane normal to the axis and back toward the outermost element creating a reverse oblique impinging jet inside said lens tip that minimizes any recirculation zone in front of the outermost element.