Egg Incubator is used for incubating Eggs to allow them to hatch. The Incubator comes in two flavors. The first is the unlimited hatching Incubator that each Trainer gets when they start the game. This is shown below with the orange bottom. The second Incubator is the limited hatching Incubator that can only hatch 3 eggs before breaking. This is known by the blue bottom of the Incubator (also shown on the bottom).

The limited hatching Incubator can be purchased at 150 Poké Coins a piece from the Shop.