A buyer requests a 20-liter cooler bag. The factory receives no container dimensions, no loading photo and no indication of how much space the cooling packs will occupy. Both sides can agree on the volume and still imagine different products.
For a custom cooler bag, capacity is most useful when it describes a real load. Start with the items the customer will carry, then turn that arrangement into dimensions and a sample-review method. The example above is illustrative, not a specification for a Weierken model.
Separate three measurements in the specification
Record external dimensions, internal usable dimensions and the intended load separately. External size helps with storage and packaging. Internal space determines whether the contents fit. A can count describes one particular arrangement of containers. None of these measurements should silently stand in for the others.
Ask how each measurement is taken: empty or loaded, open or closed, and with which removable parts fitted. A soft bag may not hold exactly the same shape in every condition. The agreed measurement method belongs beside the dimensions in the drawing.
Make a loading list before choosing the bag shape
- List the actual bottles, food containers or other items.
- Record their maximum dimensions, including lids and handles.
- Identify which items must stay upright.
- Add the cooling packs and any removable divider.
- Identify items that should be accessible without unpacking everything.
A simple top-view and side-view sketch can resolve questions that a liter value cannot. For example, upright bottles may call for a different opening and proportion from stacked lunch containers. Send a photograph of the intended arrangement when physical reference items are not available to the development team.
Allow for the opening, not only the storage space
An item that fits inside the body still has to pass through the opening. Check the largest container against the opening dimensions and review how the lid or closure operates with the full load in place. Look for contact between contents and the closure, especially at the upper corners.
Do not solve a tight fit by simply enlarging the outside of the bag. Ask the team to review the whole construction, including insulation, lining, lid and carrying points. A dimensional change can affect more than the space inside.
Write a can-count statement that another person can reproduce
If the commercial description uses a can count, keep a reference loading photograph. Record the container dimensions, quantity, orientation and whether cooling packs are included. Different container formats can produce different counts, even when the bag itself has not changed.
Use the same arrangement during sample review and when preparing product photography. Avoid showing a tightly packed promotional layout if the intended customer still needs room for cooling packs or easy access.
Compare size options using the same brief
For a small, medium and large collection, prepare a separate load for each size. Do not assume that scaling every dimension produces three equally useful products. Review opening access, carrying method and storage requirements for each version.
Ask the factory to identify which components can be shared and which need separate development. Keep those decisions in the quotation and sample records rather than treating a size extension as an identical repeat order.
What to approve before bulk production
The final sample record should include the drawing revision, measurement method, loading photograph and closure check. Agree tolerances with the manufacturer for the specific construction instead of inserting an arbitrary universal number. Use our cooler bag sample approval checklist to review the remaining details.
To start a Weierken project, send your loading list, preferred carrying method, target market and estimated quantity through the custom bag inquiry form. The development team can then review a practical size and construction rather than quote from a capacity label alone.