1/3 oz Platinum Coins

I just recently came across 1/3oz platinum coin for sale on JM Bullion.

Can someone enlighten me on it? The only fractionals I have ever seen are 1/10, ¼, ½, and 1/20 in some cases. Is the 1/3oz an actual coin from one of the country mints or something just made up by the bullion dealers?

Here’s some. Mostly Australia. 
 

https://en.numista.com/catalogue/index.php?r=&ct=coin&im1=&im2=&tb=y&tc=y&tn=y&tt=y&tp=y&cat=y&ru=&ca=3&no=&v=&i=&b=&ie=&u=&a=&dg=&m=22&f=&t=&w=10.4&mt=&g=&se=&d=&c=&wi=&sw=

Thank you. This is very helpful.