Kitting & Manufacturing
Kits vs. BOMs: which one should you use?
Understand the difference between virtual kits assembled at ship time and pre-manufactured finished goods built from a Bill of Materials.
The core distinction
ShipWave supports two ways of selling products that are made up of multiple component SKUs, and choosing the right one keeps your inventory accurate. A kit is a virtual bundle—the components stay on the shelf as individual SKUs until an order ships, at which point ShipWave decrements each component's on-hand quantity atomically. A BOM (Bill of Materials) is a recipe for a pre-manufactured finished good. You build the finished SKU ahead of time using a Manufacturing Order (MO), which consumes the components and produces a single, sellable parent SKU that lives in inventory like any other product.
When to use a kit
Use a kit when the components are easy to combine at packing time, or when you want to sell the same components in many different configurations without committing to specific bundles in advance. Examples: a "Scooter Starter Pack" (scooter + charger + helmet), a "Replacement Hardware Set" (screws + washers + Allen key), or a holiday gift bundle. The components remain individually sellable and you only pay the labor of combining them when a kit order actually ships.
When to use a BOM + MO
Use a BOM when the finished good requires assembly time, labor cost, or QC steps that you want to track—or when the finished good has its own UPC/barcode and needs to be inventoried as a standalone SKU. Examples: a custom-built battery pack with internal welding, a private-label scooter assembled from imported sub-assemblies, or a retail-ready gift box that has a printed sleeve. Once the MO completes, the finished SKU has its own FIFO cost layer that includes labor and scrap.
Component back-references
For any component SKU, open the product detail page and look for the "Used in" panel. ShipWave shows you every kit and BOM the component is a member of (e.g. "Used in 3 kits, 1 BOM") along with the ratio. This is critical before discontinuing a component—you don't want to retire a SKU that's silently driving sales through a kit.
Mixing the two
You can absolutely have a kit that contains a BOM-produced finished good as one of its components. For example, a "Pro Scooter Bundle" kit can include a BOM-built private-label scooter plus an off-the-shelf charger. ShipWave handles the nesting correctly: the kit decrements the finished scooter (not its raw components) at ship time.
FAQs
Can I switch a product from kit to BOM later?
Yes. The product itself is just a SKU—the kit-vs-BOM distinction lives on the configuration. You can disable the kit definition and add a BOM definition without recreating the SKU. Historical orders keep their original allocation.
Does a kit decrement components or the kit SKU?
Components. The kit SKU itself has no on-hand quantity—its availability is computed live from its members. See <a href="/help/creating-a-kit">Creating a kit</a> for the formula.
What if a BOM component is also sold individually?
That's the norm. The component stays on the shelf and remains sellable until you issue an MO, at which point the MO soft-reserves the needed quantity until completion.
Do kits and BOMs work with FBA inventory?
BOMs work with FBA because the finished good is a real SKU that can be sent to Amazon. Kits are warehouse-only—FBA can't assemble at ship time on your behalf.
More in Kitting & Manufacturing
- Creating a kit
Build a virtual bundle from existing components. Availability and component decrement happen automatically at ship time.
- BOMs and manufacturing orders
Define a Bill of Materials, issue a manufacturing order, and track labor + scrap as components are consumed and finished goods are produced.
- Substitution groups
Let any of several interchangeable SKUs satisfy a kit or BOM component slot. Track which one actually shipped for accurate cost and warranty data.
- Kit and BOM returns policy
Choose whether returned kits come back as individual components or as a single re-assembled unit. Lot-controlled recalls handled automatically.