Limited Quantities - These Silent Kninja Air Tracks are a great tumbling Mat. Each mat is 20ft long 3.3ft wide and 8 inches thick. These are very durable and waterproof (we use them as a slip and slide as well!). Every mat comes with a high-power electronic air pump and takes approximately 1-2 minutes to inflate or deflate. The inflatable air mat can be folded and unfolded for storage in a bag. After inflation, the inflatable gymnastics mat will maintain its pressure for days, but can easily be adjusted for more or less firmness.