7d9b4a68__and_Dynamic_Raster_Mosaicking__Description
[Function] Mask [Uses] This can be used to mask out clouds or other parts of an image on a pixel by pixel basis. [Description] 
Creates NoData by defining a range of pixel values. Any values outside the range will be returned as NoData.
On-the-Fly Processing and Dynamic Raster Mosaicking
Description