A tech pack is the written and drawn specification of a garment. For a plain tee, it does not need to be long, but it must answer the questions that change the cost: what fabric, how it is made, what size, what trims, what labels and how it is packed. Without that, each factory assumes something different, and the prices you receive are for different products.

Fabric

State the fibre content, yarn type such as combed or carded cotton, knit construction such as single jersey, fabric weight in grams per square metre with a tolerance and a named method such as ASTM D3776, and any finishing. Give the colour standard and the shrinkage limit after a named wash procedure such as ISO 6330.

Construction

Include flat sketches of the front and back, neckline type and rib width, shoulder taping, seam types such as overlock or coverstitch, hem depths and stitch density. Note whether the tee is tubular or side-seamed, since that affects both cost and fit.

Measurements

Provide a graded measurement chart with points of measure, how each is measured, and a tolerance for each. A base-size sample or a reference garment helps the factory understand the fit.

Trims, labels and decoration

List neck labels or printed labels, care and fibre-content labels, hang tags, and any print or embroidery with size and position. The fibre-content label must follow the rules of the market, such as the FTC's Textile Rules in 16 CFR Part 303 for the US.

Packing and quantities

Give folding, polybag, size stickers, carton requirements, quantities per colour and size, and target delivery. Mention the inspection standard, for example sampling under ISO 2859-1 with your AQL levels.

Keep it controlled

Give the tech pack a version number and date, and ask each factory to confirm which version its quote is based on.

With the same tech pack in every factory's hands, differences in price are easier to understand and discuss.

Ask each factory to list any assumptions or questions it has about the tech pack with its quote. Gaps it points out are worth fixing in the next version before sampling starts, so the sample is made to the same document as the quote.