Two Cores, One Decision That Shows on the Foot
两种内芯，一个上脚就看得出的决定
Diamond Rope is a rhinestone trim built around a length of core, with the stones carried on a fabric back that wraps the core. On the full-round version that core runs the whole length and you get to pick what it is. The two options we run are a cotton cord and a PVC round tube. They cost about the same. What they don't share is feel, and feel is the part your customer notices the second they slip the sandal on.
水钻抽条（Diamond Rope）是围着一根芯做出来的水钻条，钻装在包裹芯的布底上。全圆款的芯贯穿整条，而这根芯用什么，是你能选的。我们常用的两种，一种是棉芯，一种是 PVC 圆管。两者价格差不多。真正不一样的是手感，而手感正是顾客一上脚就感觉得到的地方。
So this isn't a price call. It's a behaviour call. Pick the core by how you want the strap to sit, then write it into the spec so the factory builds the one you meant.
所以这不是比价的事，是比脾气的事。先想清楚你要这条带子上脚后是什么状态，再把它写进规格，工厂才不会做成另一种。
How Each Core Behaves
两种芯各是什么脾气
A cotton cord is soft and forgiving. It bends around a curve without fighting back, and it follows the line of an ankle or an instep instead of standing off it. Stitch it down and the strap drapes. The trade is that it carries less of its own structure: on a long unsupported span it will sag a little rather than hold a clean arc.
棉芯软，好对付。绕弯它不跟你较劲，会顺着脚踝、脚背的线条贴上去，而不是支棱着。缝上去之后，带子是垂顺的。代价是它自己撑不起太多结构：一段长又没有依托的地方，它会塌一点，撑不出一条干净的弧。
A PVC round tube is the opposite temperament. It holds its shape. A strap built on PVC keeps a rounded, standing profile and reads as more substantial in the hand and on the shelf. It resists crushing in the carton. The trade runs the other way: it doesn't want to follow a tight curve, and forced around one it can kink instead of bending smoothly.
PVC 圆管脾气正相反，它挺，能保形。用 PVC 做的带子，会保持圆鼓鼓、立得住的样子，拿在手里、摆在货架上都显得更有分量，装箱也不容易压扁。代价反过来：它不愿意顺着小弯走，硬掰它会出折痕，而不是平滑地弯过去。
There's a short way to remember it: the cotton cord takes the shape of the foot, the PVC tube keeps the shape of the rope.
一句话记法：棉芯随脚走，PVC 管保自己的形。
Which Sandal Styles Take Which Core
哪种款式该配哪种芯
Match the core to where the strap actually goes.
按带子实际走到哪，来配芯。
Cotton cord earns its place on:
棉芯适合用在：
- Ankle straps and slingbacks that wrap and need to follow the body. / 绕脚踝、后绊带这类要贴合身体的位置。
- Toe loops and thin curved straps where a hard core would kink. / 趾环、细而弯的带子，硬芯在这儿会折。
- Anything stitched onto a soft upper where you want drape, not stand-off. / 缝在软鞋面上、要的是垂顺而不是支棱的地方。
PVC tube earns its place on:
PVC 圆管适合用在：
- Straight or gently curved straps across the vamp where you want a full, rounded look. / 鞋面上较直或弯度不大的带子，要的是圆润饱满的卖相。
- Styles that read "chunky" or premium on the shelf and need visual weight. / 走粗犷或高端路线、需要视觉分量的款。
- Bundled or stacked rope looks where each line should hold its own round profile. / 多条并排或叠放的造型，每根都要立得住自己的圆形。
If a single style has both a wrapping ankle piece and a straight vamp bar, it's normal to spec cotton cord for one and PVC tube for the other. They're not an either-or for the whole shoe.
如果一个款同时有绕脚踝的部分和鞋面上的直条，那一个用棉芯、一个用 PVC 圆管，是很正常的做法。不必整双鞋只能二选一。
What to Put on the Order
下单时要写清什么
Naming the colour and the stone is the easy part. The line that gets missed is the core, and missing it is how a soft strap arrives stiff. Spell out four things and the sample comes back right the first time.
颜色和钻是好写的部分。最常漏的是芯，而一旦漏了，软带子就会做成硬的发过来。把这四项写清楚，头版样基本就对了。
1. Form: full-round (core runs the whole length) or half-round (stones on one side, fabric showing). Inner core only applies to full-round. / 形态：全圆（芯贯穿整条）还是半圆（只半边包钻、露布）。内芯只对全圆有意义。
2. Inner core: cotton cord or PVC round tube. State it in plain words. / 内芯：棉芯，还是 PVC 圆管。直接写明。
3. Stone material and finish, drawn from our extensive density library so the sparkle matches your tier. / 钻的材质与表面效果，从我们的完整密度库里选，闪度对得上你的档位。
4. Width, colour and length per coil or per bundle. / 每卷或每捆的宽度、颜色、长度。
A clean line reads like this: "Diamond Rope, full-round, PVC tube core, 8mm, rose gold AB, 50m coils." That sentence leaves nothing for anyone to guess.
一行干净的写法是这样：「水钻抽条，全圆，PVC 圆管芯，8mm，玫瑰金 AB，50 米/卷。」这句话不留任何让人猜的余地。
When you're not sure which core a style wants, ask for both on the sample run. Holding a cotton-core and a PVC-core version of the same strap side by side settles the question in about ten seconds, and it costs far less than discovering the difference on a production lot.
拿不准某个款该用哪种芯时，打样阶段就两种都做。把同一条带子的棉芯版和 PVC 芯版并排拿在手里，十秒就能定，远比到大货上才发现差别便宜。
The Short Version
一句话版本
Want the strap to hug the foot and follow a curve? Cotton cord. Want it to stand round, feel substantial and survive the carton with its shape intact? PVC tube. Decide by behaviour, write the core into the spec, and the rope you picture is the rope that ships.
想让带子贴脚、顺弯走？棉芯。想让它立得圆、有分量、装箱后形状还在？PVC 圆管。按脾气定，把芯写进规格，你脑子里那条抽条，就是发出去的那条。