Open Jump ring size is 3.8mm, 20gauge.
Clasp Length without Jump ring: 10.3mm
Clasp Width: 3mm
Like Spring Rings, Lobster Clasps are held closed by a spring. Unlike Spring Rings, the closure is a strong pincer-like 'lobster claw' that opens with a small trigger lever, and closes shut on a jump ring or flat pierced tab.
Lobster clasps are often used for medium-to-heavy chains and beading lines, for heavier necklaces, bracelets, and keychains. Their claw mechanism can be shaped as a square, oval, teardrop, or other form, depending on the desired use and aesthetics.