What Singapore coin is made of copper?

All Singapore coins in the Third Series have a layer of copper, though the copper layer does not show on any coin. This series was first issued in 2013.

On the outside, the coins are either nickel or brass, with the exception of the 1-dollar coins, which are nickel in the middle and brass around the edges. The center of each coin is steel that is covered with a layer of nickel. The copper layer is on top of the nickel layer but under the outer finish of nickel or brass. The coins have electromagnetic signatures that help machines detect counterfeits.