With the projector function turned off, buyers can also use the device to charge their iPhone (it adds 100% to the life of the phone’s battery).

Japan-based accessory maker Sanwa Supply started selling the 400-PRJ011 in its online store, a DLP micro projector that slides onto an iPhone 4 or iPhone 4S. The device comes with a 2,100mAh battery, which takes about five hours to fully charge and provides enough juice for 2.5 hours of projector usage.

Sanwa says the projector produces images with 640×360 resolution, 1,000:1 contrast ratio, and up to 65 inches in size. The device weighs 103g and also features internal speakers that can be used in addition to those in the iPhone. Sanwa is selling the 400-PRJ011 for 19,800 Yen (US$260).