Amazon.com Inc (AMZN.O) said on Wednesday that more of its new third generation Kindles were ordered in the first month of availability than any previous models. The online retailer and maker of the popular e-reader introduced last month a $139 Wi-Fi version of its Kindle, as well as a lighter and smaller version of its $189 3G wireless device, which holds more memory. Amazon said it had begun to ship the new devices to customers on Wednesday, two days ahead of its original target. The Kindle continues to be Amazon's best-selling product, the company said in a release. Amazon does not disclose sales or profit data related to the Kindle, a much-hyped device that has been a growth engine for the company. But the Kindle still faces competition from a host of competitors, including Sony (6758.T), Barnes & Noble (BKS.N) and the recent launch of Apple's (AAPL.O) iPad, which includes e-reader functions. Shares of Amazon rose 1.86 percent to close at $126.85 Wednesday on the Nasdaq.