A lobster-claw clasp is a great idea if you need to frequently remove a tag from your pet's collar. These little clasps are 30mm in length and can be opened using one hand.
Ladies will also know how much damage a split ring can do to finger nails, so a lobster claw clasp is a good idea if you don't want to risk breaking a nail (or two!).
Using a lobster claw to attach your newly engraved pet tag is therefore a sensible idea.