Basically according to my mechanic, all the item that I purchased from Ebay they're factory product that he believes, is the 2nd grade that's why they don't sell it with the factory boxes. I purchased all 4 sensors for my car. From all 4 only 1 rear sensor that works perfect ! So I spend my first $300 installation cost for nothing ! The shop owner which is my friend, order the same sensors which surprisingly came with the same part #s BUT comes with factory Denso boxes. They installed them, while I was watching to collect all my new 2nd grade sensors. They let me drove my car around, no more CEL ! My advice, if the sensor you want to install has easy access, give it a try since the seller is honest and fair. But if you have to pay somebody, I'd rather have the one with factory box even though it about 50% more.