This is a 14mm long lobster clasp with a silver finish.
Lobster clasps are one of the most common clasp styles and offer a streamlined look and good security for all types of strands. Named for its resemblance to the action of a lobster claw, this clasp features a hook shape with a spring-operated closure. Simply press the ring at the opposite end of the strand against the closure, pushing it open enough to let the ring pass onto the hook (or press the release lever to open the closure). The spring holds the clasp closed until the lever pulls it open to release the ring. You can add a plain or fancy ring to the opposite side of the strand to complete this clasp.