Responding to Microsoft's figures regarding the hands-free Xbox 360 Kinect sensor, Sony has revealed that its rival PlayStation Move controller has sold 4.1 million units in the two months since its September 15 release.
The Move controller is one part of a suite of gadgets that enable the PlayStation 3 to detect motion.
It's similar to the Nintendo Wii's Wiimotes, but works in tandem with the PlayStation Eye camera for increased accuracy, and can be paired up with an optional navigation controller.
Sony said that the number does not include sales of the stand-alone PlayStation Eye or navigation controller, though did not specify whether this was counting units sold by Sony to retailers or units sold by retailers to consumers.
The Move had shipped 2.5 million units to North American, Latin American and European retailers after its first month.
One other point of note is that each Xbox 360 requires only one Kinect Sensor, while PlayStation 3 owners can use up to four Move controllers with compatible games.
Microsoft earlier announced that the Kinect Sensor had sold 2.5 million units worldwide after 25 days at retail, following its November 4 debut in North America.