Aviation Windsocks 8 foot in White or Yellow. Shorter 4' and 6' sizes are called wind indicators. They are for road works, blasting, occupational health and safety and search and rescue operations.
Other sizes available:
4-foot - Commercial Windsocks 4 Foot
6-foot - Commercial Windsocks 6 Foot
12-foot - Aviation Windsocks 12 Foot