Bandai Premium production limited release. 3 masks per set. Pre-order has started since yesterday (September 24th), and will end on December 22nd. Mid March 2011 release, 3,675 Yen per set (inclusive of tax).
Another limited item from Bandai which have begun receiving orders since yesterday is Mega Size Model 1/48 Gundam RX-78-2 Ver. RG Gundam Project, on Bandai Hobby Online Shop.
Images are from Bandai Premium.