Hi guys >From sorting through 100's of patents, I have managed to find 3 excellent sources of info on the Honda/NGK sensors. They are US Patent No. 5,083,427 and 4,963,246 and 4,140,085 You can find them at http://www.uspto.gov/patft/ I have updated my web page with this information at http://www.vb.co.za or http://196.22.202.162 Paul