Each is 1 oz of .999 silver. Think about the fact there are only 5000 of each in the entire world. They were minted for one year; not to be reproduced ever. Their availability will disappear.
2005 Kookaburra: These are very rare and extremely beautiful coins. Only 5000 minted and only 2 have been graded by PCGS so this is an extremely unique find at MS67. Not many of the 5000 have migrated to the US. This has a population (number at this PCGS grade at time of listing) of 1!
2004 Maple Leaf: Also extremely low mintage of 5000. This one is MS 64 but makes a nice pair for that person born under the sign of Libra or the one seeking a gift for him/her.