The nice thing about that mold is they come in different sizes and they aren't very expensive.
Funny thing about this, I barely had 20mls of PR left so i was frantically looking around the shop for something to cast the block of agarita in when I spotted this one empty on a back bench. The block fit almost perfectly so I measured the block and the tub. The 20mls was just the right amount for this cast.
The block popped out of the tube very easily with out the use of mold release.