Google's Second-Gen Nexus 7 May Be Limited To 3.5 Million Units

(NASDAQ:

) was expected ship as many as

of the second-generation Nexus 7 in 2013.

A new report by

indicates that may not be the case. According to the Taiwan-based supply chain publication, global shipments are estimated to come in at 3.5 million units -- less than half of the original estimate. It is also half the number of units that the original Nexus 7 sold

. The unusually low number is being blamed on the device's limited reach. Unlike the iPad and its miniature counterpart, the new Nexus 7 will reportedly skip out on the Chinese market. Google's lower-than-expected shipments are also being blamed on the increasing number of low-cost seven-inch tablets. When the first Nexus 7 arrived last year, Google's biggest threat was

(NASDAQ:

).

(NASDAQ:

) posed a threat as well, but Surface's 10-inch display and $500 MSRP put it in an entirely separate class. The same could be said for the third-generation iPad, especially after sales of that unit

. Today the Nexus 7 faces competition from

(NASDAQ:

) current iPad Mini and its anticipated successor,

(NYSE:

) Slate 7 and a rising number of cheap clones. GigaOM recently wrote about a little-known $149 tablet, the Hisense Sero 7 Pro, that is supposedly

as the original Nexus 7. Available at

(NYSE:

), the Sero 7 Pro includes the following specs:

Those specs are a bit lower than the

, but Hisense's device is also $80 cheaper. In addition to these devices, Google will also face competition from a number of tablets that are expected to ship this fall.