The back, or reverse came from a 10 sen dated 1989 to 2011 . Heres the link http://oldcoinwys.blogspot.com/p/malaysia-10-cent.html
The Obverse is correctly struck on a Copper-Nickel Planchet intented for the 10 SEN but the Reverse shows a 1 SEN intended for a Bronze Clad Steel Planchet.
1 SEN 1989 - 2008 Bronze Clad Steel 10 SEN 1989 - 2011 Copper Nickel I want to share these pictures with you from the Numista website -
A few years ago, a batch of error Malaysian coins appeared on the market. This could have only occurred if it was a mint sports - i.e. an employee in the mint purposely made such coins and released them in the market. Regardless of the origin, they are still genuine coins. As of what it is, it seems to be a 10 sen coin which the 10 sen obverse die was swapped out with the 1 sen die. 1 sen coin is slightly smaller than 10 sen which is reflected in the second photo.
Mules consisting of every conceivable combination of 1 sen and 10 sen dies were intentionally produced in the Malaysian Mint in 2005. See this link for photos: http://www.error-ref.com/?s=mules
Take another 2x2 staple it and weigh it. Tare out the weight and then put that baby on it. Very cool coin if original, still a keeper if it weren't!