The toonie (also spelled twonie or twoonie), formally the Canadian two-dollar coin (, nicknamed or ), was introduced on February 19, 1996, by Minister of Public Works Diane Marleau. it possesses the highest monetary value of any circulating Canadian coin. The toonie is a bi-metallic coin which on the reverse side bears an image of a polar bear by artist Brent Townsend. The obverse, like all other current Canadian circulation coins, has a portrait of Queen Elizabeth II. It has the words in a typeface different from any other Canadian coin. The coin is manufactured using a patented distinctive bi-metallic coin-locking mechanism. The coins are estimated to last 20 years. The discontinued two-dollar bill was less expensive to manufacture but lasted only one year on average. On April 10, 2012, the Royal Canadian Mint (RCM) announced design changes to the loonie and toonie, which include new security features. Coins minted prior to 2012 consist of an aluminum bronze inner core with a pure nickel outer ring; but in March–May 2012, the composition of the inner core switched to aluminum bronze coated with multi-ply plated brass, and the outer ring switched to steel coated with multi-ply plated nickel. The weight dropped from 7.30 to 6.92g, and the thickness changed from 1.8 to 1.75 mm. The Mint said that multi-ply plated steel technology, already used in Canada's smaller coinage, produces an electromagnetic signature that is harder to counterfeit than that of regular alloy coins; also, using steel provides cost savings and avoids fluctuations in the price or supply of nickel. Naming "Toonie" is a portmanteau word combining the number "two" with the name of the loonie, Canada's one-dollar coin. It is occasionally spelled "twonie" or "twoonie", but Canadian newspapers and the Royal Canadian Mint use the "toonie" spelling. Jack Iyerak Anawak, member of Parliament from Nunatsiaq (the electoral district representing what is now the territory of Nunavut), suggested the name "Nanuq" [nanook, polar bear] in honour of the Inuit and their northern culture; however, this proposal went largely unnoticed beside the popular "toonie". The name "toonie" became so widely accepted that in 2006, the RCM secured the rights to it. A competition to name the bear resulted in the name "Churchill", a reference both to Winston Churchill and to the common polar bear sightings in Churchill, Manitoba. Launch Finance Minister Paul Martin announced the replacement of the $2 banknote with a coin