I just came from Wal-Mart and saw the new line of Nelson retro styled garden sprinklers. They used the original designs and materials from the 1930s and newer to make some really cool
retro products. Cost is from $12 to $20 or so.
While the sprinklers look very cool, they are made from cast iron and brass. You have two problems with that material in the garden. One is the cast iron will rust, duh, but so did the originals - at least they are authentic (and did I mention cool). But something we have all forgotten about in the past 40 years since brass became the universal standard of water fittings...brass and cast iron fastened together will result in galvanic action that wastes one of the materials!
If you use cast iron sprinklers with brass fittings, your fittings will chemically weld themselves to the cast iron. The next thing that happens is the cast iron or the brass (I don't remember which one will go first) will completely disintegrate and you will have no threads on the hose or the sprinkler. In any case, the sprinkler will become useless. I did notice that Nelson put some grease inside the threads on each sprinker to slow down the galvanic action that will happen between the iron and brass.
So the warning is this. These products look cool but will not last as long as you might like. There is a temporary cure, though. If you put a plastic male fitting on your hose, the only problem you will have is rust. At least the sprinkler won't disintegrate as fast as with brass fittings. The plastic breaks the metal-to-metal contact that will really ruin both the hose and sprinkler. If you have brass fittings, get a plastic flow control valve and install it at the end of the hose.
Or you could buy the sprinkler and set it on your shelf as a conversation piece because they are very cool looking!