A Vague Spec Is a Guess, Not a Document
A tech pack that says “cotton tee” is a guess, not a document. A factory cannot quote against it, cannot buy fabric from it, and cannot sample from it — unless it asks you twenty follow-up questions first, and every one of those questions is an opportunity for a wrong assumption. The tech pack is the contract that prevents those assumptions. The moment it goes vague, the factory guesses, and the sample comes back wrong.
This is written for brand owners and product developers who need to issue a spec a factory can actually build to.
Why Vague Specs Fail
Failure almost never sits with the factory. It sits in the line you left out. Leave out the weight and the fabric comes back too thin. Leave out the seam type and the seams come back wrong. Leave out the tolerance and the measurements drift. Every omission is a decision you handed to the factory — and the factory will make it in whichever direction pays them.
The 12 Sections a Tech Pack Must Have
This is the core asset. Leave any one of these empty and the factory is guessing.
| Section | Must include | Commonly missed |
|---|---|---|
| Cover / overview | Style name, SKU, season, target retail price, reference images | No SKU or target price |
| Technical drawings | Front and back flats + annotations | Drawings with no annotations |
| BOM (bill of materials) | Every fabric and trim, with supplier references | Missing trims or colors |
| Fabric spec | Composition, weight, width, color, finishing | “Cotton” with no full spec |
| Trim spec | Labels, zippers, buttons, drawcords, with sizes and colors | “Zippers” with no spec |
| Colors | Pantone or lab-dip reference per colorway | No color standard |
| Size spec | Measurement points + tolerances (±0.5 cm) | No tolerances |
| Construction | Seam types, stitch density (SPI), hem treatment | No seam type or SPI |
| Grading / size range | Size range + grading rules | Grading rules missing |
| Print / decoration placement | Placement + size diagram | No placement diagram |
| Packaging and labeling | Polybag, hangtag, carton, care label spec | No packaging |
| Testing requirements | AQL level, test methods, pass/fail limits | No pass/fail thresholds |
The Four Sections Most Often Skipped
Fabric spec. “Cotton” is not a spec. “240 GSM combed cotton knit, 180 cm width, preshrunk, reactive dyed, Pantone 18-1124” is. If the fabric is custom, add the supplier reference and a physical swatch. Without weight and width, the factory cannot quote fabric or markers.
Construction. State the seam type and the stitch density. A side seam can be overlocked, flat-stitched, or felled — they cost differently and they perform differently. Write in the SPI (stitches per inch) and the hem type. If you do not specify it, the factory uses its cheapest default.
Testing. State the standard and the pass/fail limit: wash colorfastness, shrinkage tolerance, seam strength, pilling grade, and the AQL level for the final inspection. A test without a limit is not a test.
Packaging. Polybag, hangtag, and carton specs are part of cost and delivery. Leave them out and the quote defaults to the cheapest option, and the sample arrives with nothing inside it.
Which Tests Actually Matter
Test what the risk is. Knit tops: shrinkage, colorfastness, pilling, seam strength. Denim: shrinkage, rub fastness, seam slippage. Kidswear: flammability and small parts under CPSC 16 CFR. Agree the methods and limits with the factory, and get reports from an accredited lab.
A Straight Answer
Wingtu Apparel is one of many options. We do full-category custom apparel — tees, hoodies, pants, outerwear, shirts, polos, knitwear, denim, and loungewear — and we read tech packs down to the seam type and stitch density. We are not the factory that takes rigid or non-apparel projects. If your line is apparel, download the template below, fill it in, and send it back — or send the pack you already have and we will mark exactly what is missing.
FAQ
Q: What is the difference between a tech pack and a spec sheet?
A: A spec sheet is usually just the size chart. A tech pack is the full document — technical drawings, BOM, fabric and trim specs, measurements, construction, grading, testing. The tech pack is the contract.
Q: Do I need technical drawings, or are photos enough?
A: Photos show the style. Annotated flats show the seams, trims, and construction. The factory builds from the flats. Use both.
Q: How detailed should the size spec be?
A: Every measurement that matters, each with a tolerance. Chest, body length, shoulder, sleeve length, and hem are the minimum — plus anything specific to the style. ±0.5 cm is standard on knits.
Q: What happens when a tech pack is incomplete?
A: The factory fills the gaps the cheapest or easiest way, the sample does not match what you imagined, and then you pay to change it.
CTA
Download our free tech pack template, fill it in, and send it back — or send the spec you already have and we will mark what is missing, so you do not waste a round of sampling fees.
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