The pull test, the wash test and the two lines to write into the order.
Decorative knitwear is the easiest category to sell and the easiest one to get wrong. Lurex plating, metallic filament and applied sequins all behave differently in washing and handling, and each needs a specific check before bulk.
A metallic filament is plated alongside the ground yarn during knitting, so it is part of the fabric rather than an applied trim. That makes it more robust than sequins and easier to care for.
The risk is surface dulling. Washing hot, or tumble drying, takes the shine off quickly. The care label should specify cold washing, inside out, and no tumble drying.
Check colour consistency between lots. Metallic yarn shows lot variation more visibly than a matte yarn does, which matters when a repeat order sits next to the first delivery on the same shelf.
Sequins are attached, so attachment strength is the whole test. Run a pull test on the counter sample and agree an accepted force.
Run a wash test with the sequins in place and check for discs that have lifted, cracked or lost their finish.
Ask whether the sequin attachment is machine or hand work, because that affects both consistency and the repeat cost.
First: the accepted result of the sequin pull test and the wash test, stated as a standard rather than an intention.
Second: the exact care instruction, agreed before the label is printed rather than after the first complaint.
Festive and occasion assortments need newness every year but rarely need new bodies. A metallic version of an existing body gives a buyer a second story at a fraction of the development cost.
This is also the part of the range where photography matters most, because shine is the product.
Every style in this catalogue publishes its fibre content, which is the input all of the above depends on. Start from the full catalogue or from a section such as Women's Autumn/Winter Knitwear, then ask for the points the catalogue does not publish.

80% Rayon, 20% Sequins
Spring/Summer · View style
60% Acrylic, 20% Cotton, 10% Lurex
Autumn/Winter · View style
80% Acrylic, 20% Metallic yarn
Autumn/Winter · View style
90% Cotton, 10% Lurex
Autumn/Winter · View styleGenerally yes, because it is knitted into the fabric rather than attached to it. The main risk is dulling rather than detachment.
Cold wash, inside out, no tumble dry, as confirmed by the supplier for the specific yarn.
A pull test on the counter sample plus a wash test, with the accepted result written into the purchase order.
Send the item number and the question together. Concrete questions get concrete answers.