Every earring back is a trade between security and convenience. A butterfly back is convenient and loses earrings. A screw back takes an extra few seconds and does not.

On a plain gold ball that trade is arguable. On a stone you actually like — one you paid for, one that was a gift, one your daughter has worn since her piercing healed — it is not much of a trade at all. The flat disc back also sits flush against the lobe, which is what makes these comfortable to sleep in; 27 of these product pages call that out specifically.

Every one of them is 316L surgical-grade stainless steel, and 97 of them carry a 20G (0.8mm) post — 83 at 7mm length, and the 13 Lux styles at 5mm. All of them are made to ASTM F2923-20, the US safety standard for children's jewelry, and all of them carry a waterproof rating. 79 state that they are nickel free.

Sizes run from 2mm micro studs to 16mm, with 8mm the most common. 58 of the 99 state a stone or motif size on the page.

76 are gold-toned, 14 silver-toned.

Some are a bare CZ solitaire. Others set the stone in an enamel frame — the Whitney line pairs a coloured enamel surround with a crystal centre — and some are shaped motifs with CZ accents, like the Tessa heart and the Mary star. If the stone matters to you, the product page names it.

Prices are $32 for most styles, $39 for the Lux line.

All screw back flat back studs — the full 314, in every material and motif.

Kids hypoallergenic earrings — 261 styles, the same mechanism filtered to children's.

Gold flat back studs and silver flat back studs — the same range split by finish; 13 of the silver styles are set with CZ.

Pearl earrings · Game day flat backs — 7 of the CZ styles are also game day.

Sparkle is one reason to buy and the metal is the other — jewelry for sensitive ears collects everything built on the same steel.

Not on a screw back. The back threads onto the post and has to be turned off deliberately, which is a different mechanism from the push-on butterfly back that most CZ studs ship with. That is the single reason to choose these over a conventional stud — the stone is the same idea, the retention is not.

Yes. All of them are made to ASTM F2923-20, the US standard for children's jewelry, which limits lead and cadmium content, nickel release and small parts. 80 of the 99 are sold as children's styles. The screw back is the other half of the answer — a back that cannot be pushed off is the reason these suit a child who is still learning not to fiddle.

Yes. All of them are rated waterproof for shower, pool, ocean and sweat. The metal is 316L surgical-grade stainless steel, which is what makes that possible — it does not rust or discolour in chlorine or salt water the way plated brass does.

8mm is the most popular size here and reads as a clear everyday stud. 2mm to 5mm sits closer to the lobe and works for a second or third piercing, or for a young child. Above 10mm you are into a statement stud. 58 of these product pages state their size.

The back is a flat disc rather than a protruding butterfly, so there is nothing to press into your ear against a pillow — that is the design intent of a flat back, and 27 of these product pages mention sleeping in them. The post is 20 gauge, standard for a healed lobe piercing.