Barrel Clasp: Used on most rope chains to make the chain more secure. The barrel clasp looks like part of the chain and twists to get a pendant on and off.

Lobster Claw Clasp: As a traditional clasp style found in bracelets and necklaces, the lobster claw is generally reserved for heavier styles that may need added strength. The closure's shape is more oblong, similar to a teardrop shape, and is controlled by a tip that opens and closes the spring in the clasp.

Magnetic Clasp: A magnetic clasp relies on a strong internal magnet that works to pull both ends of the clasp together. In most cases, a magnetic clasp is used for light to medium weight jewelry pieces that do not put excessive stress on the magnet.

S-Clasp: An S-shaped piece of metal that connects a chain by hooking metal rings on each end of the S-shape.

Slide Insert Clasp: This type of clasp is exactly as it sounds. With a box-like shape that is hollow on the inside, the wearer will slide the nearly-flat tab into the box until it clicks, indicating a secure closure. On some jewelry, a slide insert clasp will be accompanied by a side safety catch, which adds strength and security to the clasp.

Spring Ring Clasp: One of the most common closure types, the spring ring clasp is typically used for light to medium weight bracelets or necklaces. It is round in its design and features a small tip which controls the opening and closing of the spring. The circle then closes around another smaller loop or link at the other end of the strand.

Toggle Clasp: A toggle clasp is a narrow piece of metal, usually designed in the shape of a bar, which is then pushed through a circular ring to act as a fastener. Unlike the lobster claw or spring ring clasps, a toggle clasp is not controlled by a spring. The pretty design is less secure than other closure types, but is usually meant to be a big part of the design and is meant to "show". The clasp is an attractive way to secure a chunkier link bracelet or necklace.

Necklace Sizing
The length of a necklace or chain you buy depends upon a number of factors, including what you will be wearing with it and your neck size.

To measure your neck, wrap a soft, flexible tape measure around the base of your neck. This is the same measurement used for collar sizes in men's shirts. A good rule of thumb is to buy a necklace or chain a minimum of two sizes up from your neck measurement.