Electrical plugs in Finland need two round prongs. They can be the ungrounded Europlug Type C or the grounded Schukoplug Type E/F. So do you need an electric transformer or just a shape adapter for Finnish outlets?
If you bring small appliances or small electronic items, be careful with outlets in Finland. The shape-changing adapter won't be enough to help your appliance handle the strong 220v current in Europe. As such, you'll need a "step-down transformer" (also called a converter) to reduce the 220 volts from the outlet to the 110 volts U.S. appliances deal with. While a little more expensive than the simple plug adapters, you can compare prices of power converters here.
Tip: Don't bring any type of hair dryer to Finland. Their power consumption is extremely high and can only rarely be matched with correct power converters that let you use them with Finnish sockets. Instead, simply check if your Finnish hotel has one in the room, or just buy a cheap one after you arrive in Finland.
