Tumbl Trak Air Pit with Electric Pump, Red, 5-Feet Width x 10-Feet Length x 24-Inch Height The Air Pit is the solution to a problem encountered by coaches for years--the stack of mats that have become necessary for teaching vaulting, tumbling, bars, and even beam The Air Pit has a 4-inch wide line down the top, numbers for measuring distance and if you flip it over there are depressions about a foot in diameter The mat can be used alone for dozens of drills, or it can be the base mat for a higher stack; add 12-inchers, 8-inchers, 4-inchers in any combination to make a tower of mats as high as needed It is much lighter to move, and thus much more portable than a foam mat or a stack of foam mats Designed for use under the supervision of a trained professional