The Asus P2B in a Pocket, or mini portable, projector with a maximum dimension of only 5.6 inches and a weight of under one and a half pounds.  The P2B has a footprint a little larger than a case for a CD and is 1.36 inches thick, which makes it larger than the tiny Pico projectors so instead I'll refer to it as 'Pocket" or 'mini-portable'.  It does have a separate AC power supply similar in size to those used with a laptop PC.  The P2B has a built-in battery that, when fully charged, can operate the projector for about 1.5 hours.