Here's from the SQ website:
From June 2002, SIA will progressively install a 110 V AC In-seat Power Supply System to replace its existing 15 V DC system. The new system supports Australian 2/3-pin, European 2-pin, Japanese 2/3-pin and US 2/3-pin plugs. An adaptor is required for plugs that are not compatible with the system and it can be purchased from KrisShop on board or via mail order.