Now through July 31st, use coupon code "HONDAAFX" at checkout to receive 15% off NGK's AFX Air/Fuel Ratio Monitors.

Here' is NGK's write up on it:
NGK Spark Plugs is introducing its new Powerdex AFX Wideband Air-Fuel Ratio Monitor for the performance aftermarket. This product meets the increasing demand in the market for precision air-fuel ratio monitoring tools.

Traditionally these types of tools commanded price tags that could only be justified by professional race teams and engine specialists. As technology advanced, many low-cost air-fuel ratio products emerged. Some used actual wideband sensors while others simply read OE style narrowband oxygen sensor signals and attempted to convert them to linear readouts often with marginal success.

With the AFX, NGK now offers the most affordable wideband system to date. A flexible and rugged system complete with everything needed to get you tuning. The kit comes with a digital display control module, 13' wiring harness, wideband air-fuel ratio sensor, exhaust boss and plug, and a comprehensive tuning manual. The tuning manual includes installation instructions and contains a detailed guide to performance air-fuel ratio tuning.

The AFX measures and displays air-fuel ratio (AFR) from 9.00 to 16.00. It demonstrates superb response and accuracy within 0.1 AFR. The air-fuel ratio information can then be utilized by the user to make fuel delivery adjustments to the vehicle's carburetor, mechanical fuel injection, or programmable electronic fuel injection system. The desired air-fuel ratio can be achieved depending on the performance requirements of the engine or race application. This is an exceptionally useful tool for carbureted engines, where there is a lot of freedom in tuning as well as a great need for proper adjustment.

Link to NGK's FAQs:
http://www.ngksparkplugs.com/product...x.asp?mode=nml