It opens by unscrewing a swivel ball, which opens the locket. You can switch out contents for whatever you are wearing.
Dimensions: The height from top to bottom is 42mm. The glass part is 25mm (so contents inside must be less than 25mm). A small feather is about the thickest object you can put inside (maybe about 2-3 mm of space). Stamped .925.
This listing only includes the locket. The pictures with contents inside are for example.
SEE MY JEWELRY