I had thought about buying the least expensive OBD II on Amazon. I bought it for my daughter's 1995 Volvo 850 GLT. It has an onboard computer system that will show you the codes. It is very difficult to turn the Check Engine Light off. I replaced the heated O2 sensor and just wanted to turn the Check Engine Light off. A reviewer had said how easy this model was to use and read. I am glad I sent the extra money. It was "easy" to read and to use. Thanks for putting those reviews on Amazon.