In April, David Gunnarsson introduced a new mask for Niemi (although he still seems to be wearing the first mask here in May.)
Article about 2nd mask found here.
…a tribute to the Finnish people and the legendary heroes of the Finnish Winter War from year 1939 to 1940…Finnish soldiers on one side skiing in their white winter uniforms. The Finnish chief commander Gustaf Mannerheim that later became the Finnish President…
Below is the mask Niemi wore for the first part of the season.
Artist: David Arrigo
This was tweeted by the San Jose Sharks, and I have no other information at this time.