Plate compactors fall into one of three categories: single plate compactors that move in only a forward direction, reversible which move in forward and reverse, and high performance/heavy-duty plate compactors. The handle of a plate compactor plays a key roll. It can be mounted in the center or back of the unit. It can be a swinging handle allowing for easier maneuverability. And it could also be an anti-vibration hadle for increased operator comfort. Equipment is a key element in paving and pavement maintenance.
When hovering, hummingbirds hold their bodies upright and flap their wings horizontally in a shallow figure-8. As the wings swing back they tilt flat for a moment before the wings are drawn. Most hummingbirds flap their wings about 50 or so times a second.
During migration, some hummingbirds make a non-stop 500 mile flight over the Gulf of Mexico. During courtship dives they can reach speeds up to 60 miles per hour and can average speeds of 20 to 30 miles per hour. They are the second largest family of birds with 343 species.