Most first-time buyers in this category compare kits by looking at the photo and the piece count. That is the fastest way to buy the wrong thing. A six-piece kit and an eight-piece kit can differ by less than a dollar in material cost and by a great deal in whether the repair holds after one winter.
This guide walks the sequence in the order that matters: format, resin, verification, packaging, documents. It is written from the manufacturing side, so it will occasionally tell you that something you were about to ask for does not exist in this category.
First, separate three products that all get called a repair kit
The category name hides three different products with different buyers, different price points and different failure modes. Decide which one you are buying before you request a quotation, because a factory quoting you for one will look expensive against another.
| Format | Typical buyer | What decides quality | Where it fails |
|---|---|---|---|
| Home / 3-piece on-card | Retail, e-commerce, marketplace sellers | Resin viscosity and the seal on the card | Resin dries out before use; bridge flexes |
| Professional bridge set | Body shops, glass shops, mobile repair | Bridge rigidity and vacuum seal at the neck | Leaking seal; resin pulled back out on release |
| Bulk consumables | Distributors restocking a range | Batch consistency across cartons | Batch-to-batch variation in cure time |
A kit sold to a glass shop is a tool. A kit sold on a marketplace is a consumable the buyer uses once and judges on a photo. They are not the same purchase, and one factory rarely serves both well at the same price.
The resin is the part that decides everything
In a repair kit, the plastic parts are commodity. The resin is not. Two kits that look identical on a shelf can behave completely differently, and the difference shows up two seasons later when the repair turns cloudy or the chip re-opens.
Three things about resin matter to an importer, and none of them appear on the product photo:
- Shelf life and storage. Resin is a chemical with an expiry. Ask for the shelf life in writing and confirm the production date on the cartons you receive, not just on the sample.
- Transport mode. Resin falls under chemical transport rules. It ships fine by sea in the quantities a normal order needs; air freight in large volumes requires paperwork that a small factory may not be able to produce. If you plan to air-freight, raise it before the order, not after.
- MSDS availability. If the factory cannot send you an MSDS for the resin, stop there. It means either the resin is repackaged from an unknown source, or the factory has never shipped internationally.
A factory that answers the resin question with a specification sheet is worth more of your time than one that answers it with a price.
What to verify before you send a deposit
Supplier verification in this category is unglamorous and mostly free. The point is not to build a dossier; it is to confirm that the entity invoicing you is the entity making the product.
- Match the business licence to the invoice. The company name on the quotation, the bank beneficiary and the business licence must be the same legal entity. A mismatch is the single most common cause of lost deposits.
- Ask what they manufacture versus what they assemble. Many traders present as factories. Both can serve you well, but the price, the lead time and who controls quality are different, and you should know which one you are dealing with.
- Ask for the patent numbers, then check them. Tool patents can be looked up in the Chinese patent database by number. A factory holding a real utility model on the bridge is a different risk profile from one that does not.
- Request a video walk-through, not a photo set. Photos are curated. A live call where you ask them to open a carton at random tells you more.
Packaging decides your landed cost, not your unit price
For small, light products the freight calculation is driven by volume, not weight. A blister card that stands proud of the product can add enough cubic volume to change your landed cost per unit by a meaningful margin, and the change is invisible in a unit-price comparison.
Before you compare two quotations, ask each supplier for the carton dimensions, the units per carton and the gross weight. Convert both to a landed cost. In this category the cheaper quotation is regularly the more expensive shipment.
| Data point | Why it changes the decision |
|---|---|
| Carton dimensions (L x W x H) | Drives volumetric freight, the largest variable cost |
| Units per carton | Sets your handling cost and your storage footprint |
| Gross weight per carton | Decides whether you exceed manual handling limits |
| Production date on cartons | Resin is dated; old stock is a write-off |
Documents that travel with the shipment
Customs does not care how good the product is. It cares whether the paperwork matches. For this category the routine set is a commercial invoice, a packing list, an MSDS for any resin-bearing item and a COA where the buyer's market requires one. Each of these is covered in more detail in our export documents guide.
What a factory cannot give you is a certification it does not hold. If a supplier offers you a certificate that is not in their own name, that certificate will not survive a buyer's audit.
A realistic first order
The most common mistake is treating the first order as a price negotiation. It is not. The first order exists to prove three things: that the product matches the sample, that the paperwork clears, and that the factory hits the ship date.
Order small enough that a failure is survivable, large enough that the packaging economics make sense. Then reorder. A supplier relationship in this category is built on the second order, not the first.