Are you asking about production lots ?

Production lots give you the ability to group (or batch) items so that you can trace a particular order to that batch, or identify all orders that came from a batch.

This is useful in the case of tracing the source batch of goods that are bad or needing to identify orders to contact in the event of a product recall.

https://doc.openerp.com/6.1/book/5/5_15_Manufacturing/5_15_Manufacturing_logistic/