Cast ABC is a level 1/6 puzzle in Hanayama's Cast Puzzles series. This particular version is branded as Puzzle Master, but it appears to be the same as the Hanayama's version, only with a different finish. The Hanayama version has a brown finish, while the Puzzle Master version is silver.
The goal of this puzzle is to separate the C piece from the AB piece. The starting position is with the C linked to the hole at the top of the A, not the position shown in the photo.
It works a lot like your standard ring-with-a-gap/grooved-maze design, with an additional little hiccup: not all of the grooves are actually traversable. This makes it a tad more difficult than it would otherwise be, since you'll likely be fooled by a few of these along the way.
Despite this, I would still say it is a bit easier than Cast Bike and Cast Claw, since there are fewer tricky moves. It is nicely designed so that you'll progress along quickly for a few steps before arriving at an apparent dead end, but a bit of creative thinking will quickly get you moving again to the solution. This should come quite naturally if you have done other puzzles like this before (it took me under a minute), but I've seen people stymied by it for 10-20 minutes.
Overall, Cast ABC is a fun little puzzle that would be good to give to a novice puzzler, but more experienced puzzlers may want to skip it in favor of Cast Bike.
19 hours ago