de698a76_2000_Laser_Surface_Velocimeter__Description
[Model] LSV-A-120 Air Wipe with quick exchange window [Description] 
A front-mounted, aerodynamically optimized air wipe unit keeps the sensor’s optical window free of dust and steam. For cleaning or replacement, the quick-release window can be easily exchanged.
Polytec: LSV-2000 Laser Surface Velocimeter
Description