This set contains 40 Clasps – 10 of each color and size. Silver tone and Gold Tone in 10mm and 12mm. The clasps are is packaged in a reusable storage box measuring 2.8” x 2.8” x 0.8”. These Lobster Claw Clasps are made of durable 304 Stainless Steel with vacuum Ion plating for extra durability and long lasting wear. A lobster clasp is one of the most common and strongest jewelry clasps available and one you’ll notice on most pieces of your jewelry. It gets its name from its shape since the clasp gives the illusion of a lobster claw with the pinching style of the hook. Lobster claw clasps (also called trigger clasps) are one of the most secure clasp options you can choose. They don’t rely on tension to stay closed but have an actual locking lever mechanism. They can’t slide off and can usually withstand a good tug. The lobster clasp is opened or closed by pressing down on the lever, which cause the bottom part to move inside.