Camber kits are used to correct wheel alignment on lowered vehicles, or to provide camber adjustment for tracked vehicles which require slightly negative camber. Correcting the camber on a vehicle is important for even tire wear and maximum traction.
Camber gets somewhat of a bad rap within the automotive industry. The typical premature wear pattern people notice on a lowered car is due to excessive inner tire wear. The reality is that a bad toe setting will wear tires much faster than camber will. Actually, camber can be a very good thing.