“SIT” is a newly developed, very simple, inexpensive and reliable system for Self-inflating Tires. SIT is an integral tire component that uses atmospheric air to automatically inflate the tire. As a main source of energy it uses only wheel rotation, so there is no compressor or similar additional device needed. This ensures maintenance-free, constant tire pressure over the lifetime of the tire, with great benefits. It reduces tire wear, increase fuel economy, makes your drive more safe and steering more accurate. Note: In the US alone, 4.5 million tires have to be replaced before their designed lifespan as a result of under-inflation. 87% of all tires have a history of under inflation. Poor tire pressure also costs US an extra .7 billion in fuel annually. Source: www.selfinflatingtire.com