Bracelet Clasps Compared: Lobster, Box, Spring Ring, Magnetic
A clasp is the only part of a bracelet that does two jobs at once: it holds the weight and it is the thing you operate. Those two requirements pull against each other, which is why the choice is always a trade rather than an upgrade.
Lobster
A sprung gate hinged inside a cast body, opened by pinching a lever, 10 to 14 mm long on a bracelet. It hooks onto a ring rather than closing on itself. Reliability is high because the gate is under constant spring tension and the load sits on the body: a well-made 12 mm lobster in silver carries several kilograms without deforming. One-handed operation is the best of the four once practised, though the pinch needs fingernail strength.
Its weak point is the ring it hooks onto, covered below.
Box, or push-button
Two halves: a flat tab on one side slides into a box on the other, where a sprung tongue drops into a slot, released by pressing a button. Load is carried in compression across the box walls, which gives the highest strength for the least metal — this is why a box clasp is the only sensible closure on a bracelet carrying 44 set stones. One-handed operation is moderate: the button must be held down while the tab is inserted, which takes two attempts the first few times and one thereafter. The failure mode is clogging, since soap residue and lint collect in the slot and the tongue stops seating fully.
Spring ring
A circular tube with a plunger pushed across the opening by a coil spring inside, 6 to 12 mm across, opening only 2 to 3 mm. It is light, cheap and unobtrusive, which is why it appears on fine chains. It is also the weakest of the four: the spring is small, the tube wall is thin, and the ring goes out of round the first time someone levers it open with a fingernail instead of pulling the tab. An out-of-round spring ring leaves a gap, and a gap is how a chain leaves a wrist. Suitable up to about 2 g of chain; not suitable for a bracelet that swings.
Magnetic
Two magnets in a tube or a pair of flat plates, closing without any mechanism at all. Holding figures are quoted in direct tension, typically 1 to 3 kg for a jewellery-grade pair. That number is real but misleading: the same pair releases at a fraction of it under shear or peel, which is exactly how a bracelet is loaded when it swings against a wrist bone or catches on a sleeve. One-handed operation is the easiest of any closure, and it is the only one that can be done by someone with limited hand strength.
Side by side
| Clasp | Typical size | Holds | One hand | Fails by |
| Lobster | 10–14 mm | High; gate sprung | Easy with practice | Gate spring, or the ring |
| Box | 8–12 mm | Highest per gram | Moderate | Slot clogs; tongue wears |
| Spring ring | 6–12 mm | Low, under 2 g chain | Hardest | Goes out of round |
| Magnetic | 8–15 mm | High in pull, low in shear | Easiest | Slides apart sideways |
Why magnets do not belong on anything valuable
A magnet releases along the plane where its two faces meet. Pull straight out and it holds; slide one face across the other and it lets go at a fraction of the quoted figure. A bracelet on a wrist is almost never loaded straight out, and a magnet gives no warning that it is nearly open.
The second reason is consequence: a magnetic clasp that releases drops the piece silently. On a light chain that is an inconvenience; on a tennis bracelet it is every stone in the row on a pavement.
Changing a clasp
Conversion is routine. A lobster can be swapped for a box clasp by cutting the end rings and soldering new ones; the length is unaffected and the work is a bench job of twenty minutes. The constraint is physical — a box clasp needs 8 to 12 mm of flat run, which a fine cable chain does not have, and a spring ring cannot hold a chain over about 2 g. On a tennis bracelet the link count has to be preserved or the fit changes with it.
Cost is dominated by labour rather than the part: the clasp is cheap, the soldering and refinishing are not.
The ring nobody checks
A lobster is only as good as the ring it grips. An open jump ring will straighten under load, and it does so gradually, so the bracelet feels secure until the day it is not. A soldered ring removes the failure — and if a bracelet has been lost once while the clasp looked fine, the ring is where to look.
What we make
We make bracelets in our own factory in Guangxi, which we have operated since 2008, in 925 sterling silver, 9K, 14K and 18K gold and PT950 platinum. Stones are GRA-certified D-colour VVS1 moissanite or IGI-certified lab-grown diamonds. Closures are chosen to the piece rather than to a price point: box clasps with safety catches on anything carrying a continuous row of stones, lobsters on chains, and no magnetic closures on set pieces. Prices run from $17 to $2,020, with a typical piece around $98.
Free shipping over $99, $5.99 below. Returns accepted for 30 days on unworn pieces in original packaging. Clasp type and dimensions are stated on each piece, and a clasp can be changed before dispatch — which is cheaper than changing it afterwards.