Material Guide
Korean PBT Lash Fiber 101: What the Fiber, Diameter and Finish Actually Mean
Direct answer: every eyelash extension is a PBT fiber — polybutylene terephthalate. What separates trays is the grade of that fiber, the diameter it is drawn to, and the finish it is given. LashPlus uses Korean-imported PBT in every line from 0.02 to 0.20mm, and the fiber origin is documented and can be evidenced on request.
Qingdao Hopeshair Cosmetics Co., Ltd · A private-label manufacturer's material guide
What PBT is — and what "silk" and "mink" are not
PBT (polybutylene terephthalate) is a thermoplastic polyester. It is drawn into a fine filament, cut to length, curled with heat and set — that filament is the lash extension. "Silk", "mink" and "faux mink" on a tray are marketing names for grades and finishes of the same PBT fiber, not different materials. When a buyer asks a supplier "what is it made of?", the honest answer is always PBT; the useful questions are which grade, which diameter and which finish.
Why brands ask for Korean PBT by name
Direct answer: because the fiber is the part of a tray a buyer cannot see and cannot test at a glance. Asking for the Korean-imported grade by name is how brands pin the spec down before a sample arrives. It is also how they avoid the situation where "PBT" on a listing hides a fiber swap between the sample and the production run.
- One fiber, every line: LashPlus runs Korean-imported PBT across classic, volume, easy fan, premade and promade fans — the same fiber from 0.02 to 0.20mm.
- Documented origin: the fiber origin is part of the supply-chain record — fiber origin, production site and processing sequence can be documented for a given order, and a one-page Supply Chain Statement is sent with quotes and samples.
- Raw-material buyers: LashPlus also supplies the fiber to other factories in the Pingdu cluster — a raw-material inquiry is answered on the same line as a tray inquiry.
Diameter: the number that sets weight
Diameter is the thickness of one extension in millimetres. It decides how heavy the lash sits on the natural lash, how dark the line reads, and how many lashes a fan can carry. Thinner reads softer; thicker reads darker and more defined. The full comparison is in the thickness guide; the summary:
| Diameter | Technique | What it is for | LashPlus lines |
|---|---|---|---|
| 0.02 · 0.03mm | Mega volume | Hand-made fans of 9D–20D; the fan, not the single lash, gives the density. | Volume lashes |
| 0.05mm | Volume | The volume workhorse — 3D–8D fans. | Volume · Easy fan · Premade · Promade |
| 0.07mm | Light volume · premade fans | 2D–5D fans with a darker, more defined line; the premade bestseller. | Premade · Promade · Easy fan · Volume |
| 0.10mm | Classic (fine) · fans | The lightest one-to-one diameter; also run as a fan diameter. | Classic · Easy fan · Premade |
| 0.12 · 0.15mm | Classic | Mainstream and traditional classic diameters. | Classic |
| 0.18 · 0.20mm | Bold classic | The heaviest one-to-one diameters, for strong natural lashes only. | Classic |
"Matte" and "deep black" are specs, not slogans
Direct answer: "matte" describes the surface — non-glossy — and "deep black" describes colour depth. Both are order specifications, like curl and diameter, and both should be written on the spec sheet rather than assumed from a product photo.
- Flat / ellipse lashes read matte and darker by construction: the flattened cross-section gives a lighter lash with a darker line. See the lash-extension range.
- Colored and nuance lines are produced to spec per private-label run — ask for the current range.
- Judge it on a tray, not a screen: order in-stock sample trays — next-day dispatch, up to 10 per round — and compare finish under studio light. The sample fee is credited in full on a wholesale order and doubled, up to US$50, on a custom MOQ order (no order, no refund).
What to write on a private-label spec sheet
- Fiber: Korean-imported PBT (ask for origin documentation with the quote).
- Diameter × curl × length: one combination is one specification; private-label from 5 trays per specification inside a 100-tray order.
- Finish: matte or standard; black or a named colour.
- Rows per tray: 16 is the Europe/US standard; 12, 18 and 20 are available.
- Compliance paperwork you need for your market: see the compliance checklist and the certifications page.
FAQ
What is Korean PBT fiber, and why do lash brands ask for it by name?
Direct answer: PBT is polybutylene terephthalate, the synthetic fiber eyelash extensions are made from. Brands ask for the Korean-imported grade by name because the fiber is where softness, diameter consistency and a clean black come from — and because "PBT" alone does not tell a buyer which grade is in the tray. LashPlus uses Korean-imported PBT across every line, from 0.02 to 0.20mm; the origin is documented and can be evidenced on request — see LashPlus supply-chain traceability.
What do diameters like 0.03, 0.05, 0.07 and 0.10mm mean for softness and weight?
Direct answer: the diameter is the thickness of one extension in millimetres, and it sets weight before anything else. 0.02–0.03mm are mega-volume diameters for hand-made 9D–20D fans, 0.05mm is the volume workhorse, 0.07mm is the light-volume and premade-fan diameter, and 0.10–0.20mm are the classic one-to-one diameters. Thinner reads softer and lets a fan carry more lashes; thicker reads darker and more defined. Line by line: the LashPlus lash thickness guide.
What makes a lash "matte deep black" rather than standard black?
Direct answer: "matte" describes the surface — a non-glossy finish — and "deep black" describes the colour depth, and both are specifications you state on an order, like curl and diameter. Flat (ellipse) lashes read matte and darker by construction because of their flattened cross-section; colored and nuance lines are produced to spec across the LashPlus lash-extension range. Judge the finish on a LashPlus sample tray: the fee is credited in full on a wholesale order and doubled, up to US$50, on a custom MOQ order.
Want to feel the fiber?
Order sample trays and judge the fiber before you commit.
In-stock samples ship next day; the fee is credited in full on a wholesale order and doubled — up to US$50 — on a custom MOQ order (no order, no refund).
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