In CushionsERP, when you set “Use lot/serial number” to “Yes (Lot required)” for a product, the system enforces strict lot tracking across all inventory movements for that item. This setting significantly affects how the product is handled throughout CushionsERP.

When you set this:

_Product → Card → Use lot/serial number = Yes (Lot required)_

Then CushionsERP requires a lot or serial number to be specified for every stock-related operation on that product.

Here's how it affects each key module and action:

✅ **Stock Receipts / Supplier Orders**
- You must enter lot numbers when receiving stock.
- CushionsERP will not allow the stock to be validated without assigning at least one lot number.
- This is enforced in:
  * Supplier Orders → Receive Products
  * Stock Transfers
  * Manual Stock Adjustments

✅ **Customer Shipments**
- When shipping the product to a customer, you must choose the lot(s) from which the quantity is taken.
- Lot traceability ensures accurate FIFO/LIFO and recall capability.

✅ **Inventory Movements**
- Stock movements must always be associated with a lot.
- The system will refuse any movement (in or out) that does not reference a valid lot.

✅ **Manufacturing Module (if enabled)**
- Raw materials and finished goods using this setting must:
  * Consume lots of components.
  * Produce goods into lots (you assign new lot numbers for each production batch).

- Enables traceability: You can track which lot went to which customer, and when. - Crucial for industries with expiry, quality recall, or batch compliance (e.g., pharma, food, electronics).

The system will: - Show a validation error. - Prevent you from completing the operation (e.g., delivery, stock movement). - You must input a valid lot/serial number or the action won’t proceed.

- You can manually input or use CushionsERP’s lot number generation (if a module or custom logic is in place). - Some users create lots during reception (e.g., LOT2025-001, LOT2025-002, etc.).