This is a tool for use in model assembly.
From the manufacturer:
Create wonderful effects with PECO Scene Static Grass using the Pro Grass Micro Applicator. The nylon grass particles are statically charged as they pass through the grid, landing on the pre-glued scenery in an upright position.
By carefully blending colors and sizes, realistic scenery can be easily achieved.
Note: Requires a 9V battery (not included).