Plastic Packaging Terminology
The fixed definitions we use in every quote and specification — so a mold, a product and a stock cavity mean the same thing to both sides of the table.
Why these definitions are fixed
A packaging project moves through several handoffs — sales, engineering, tooling, production and quality. If the same word means different things at each step, a specification drifts and a shipment surprises someone. The seven terms below are used identically across this site, our quotes and our product records.
Stock mold
An existing, standardized cavity we already hold — it may run for other customers and in other colors. A stock mold normally runs from an MOQ of 5,000 pieces with no tooling charge, which is usually the fastest and lowest-risk way to start a project.
Private mold
A mold built for one programme only, held in-house and not resold or reused for another customer. Ownership and any transfer terms are commercial terms confirmed in writing against your specific project. We do not advertise a free-mold programme or lifetime mold ownership.
Mold
A production tool, not a product. The count of molds is not the count of products: one mold can serve many product records and many orders. When we write about molds, we mean tooling in the library, not items for sale.
Product
A finished, sellable or displayable packaging item — a bottle, jar, closure or dispenser with a defined material, capacity and neck finish. A product is something you can open, quote and sample, not the tool that makes it.
Published product
A product record currently shown on this site — a real, specified item you can open, request a quote for and sample. A published product is a live record, not a placeholder or a future plan.
Stock product
A product built on an existing mold, so it can usually be sampled and quoted without new tooling. Stock products are the practical starting point for most projects because the cavity already exists.
Custom product
A product taken through design and mold development for a specific shape, finish or function. A custom product is quoted per project, because the tooling, validation and lead time depend on the geometry you need.
Molds vs products: the number that matters
We hold 2,000+ stock molds in the tooling library. That is a count of molds, not of products. The products published on this site are a different, smaller set. When you see “2,000+ stock molds” on this site, it always refers to cavities in the library — never to 2,000+ products. Where we refer to published product records, we say so explicitly.
Where these terms show up
Terminology questions
What is the difference between a stock mold and a private mold?+
A stock mold is an existing cavity that may run for other customers, including in other colors. A private mold is built for one programme only, held in-house, and not resold or reused for another customer.
Is a mold the same as a product?+
No. A mold is a production tool; a product is the finished item it makes. One mold can serve many product records and many orders, so the mold count and the product count are never the same number.
What is a published product?+
A product record currently shown on this site — a real, specified item you can open, request a quote for and sample. It is a live record, not a placeholder.
What is a stock product vs a custom product?+
A stock product is built on an existing mold and can usually be sampled and quoted without new tooling. A custom product is taken through design and mold development for a specific shape or function, and is quoted per project.
Does Shijin own the mold I pay for?+
A private mold is built and held in-house for your programme and is not resold or reused for another customer. Ownership and any transfer terms are confirmed in writing against your specific project. We do not advertise a free-mold programme or lifetime mold ownership.
How many molds does Shijin hold?+
We hold 2,000+ stock molds in the tooling library. That is a count of molds, not of products; the published product records on this site are a separate, smaller set.
Need the right term for your project?
Send the requirement and we will tell you whether a stock cavity can serve it — and if not, what custom development it needs.
Part of About — Custom Plastic Packaging Manufacturer
Keep reading
Material, engineering and buying pages that this one sits next to.
Products behind this page
Real items from the Shijin stock-mold library. Shown specifications are the published ones; a quotation is built from your own drawing and fill volume.
15ml PET Bottle
Published specification, stock mold, MOQ 5,000 pcs.
View product →500ml PET Bottle
Published specification, stock mold, MOQ 5,000 pcs.
View product →300ml PET Bottle
Published specification, stock mold, MOQ 5,000 pcs.
View product →1000ml PET Bottle
Published specification, stock mold, MOQ 5,000 pcs.
View product →700ml PET Bottle
Published specification, stock mold, MOQ 5,000 pcs.
View product →120ml PET Bottle
Published specification, stock mold, MOQ 5,000 pcs.
View product →Projects this topic appears in
Programmes we ran with brand and importer teams, with material, sampling and volume recorded.
USA Skincare Brand: 15-50 ml PETG Serum Dropper | Shijin
PETG serum dropper, 15-50 ml, United States
Read the project record →Germany Personal Care: HDPE Body Wash, Four Reorders | Shijin
HDPE body wash, four closure options, Germany
Read the project record →Netherlands Cleaning: PCR PET Trigger Spray at 30% Recycled | Shijin
PCR PET trigger spray, Netherlands
Read the project record →Tell us the bottle you need - we will quote it
Send the capacity, material, neck finish and expected annual volume. MOQ is 5,000 pcs and sampling runs 3–10 days. You will get a written quotation against your own specification, not a catalogue price list.