<p>This has got to be a must for every Formula 1 fan. Its a Williams Formula 1 steering wheel battery. How it works: Near empty battery, the steering wheel displays 1 illumination on the LED rev counter, and 1st gear is selected. Full battery, the steering wheel displays full revs(in the red!) and 6th gear selected. See screenshots. Made for and tested on iphone 3GS on 4.3.3 Any comments or requests, feel free to email me. Upgrade for iPhone 4 will be added soon.</p>