Auto Build inventory - we rent out

Good morning

We build an inventory item and then we have an actual cost of the new item.  But we rent the item out over a fixed term of 6 to 12 months, I don't want the full cost of the Built Item to go against the rental income (it would always show negative) - how/what do I do to more or less amortise the cost over the rental period?

Thanks in advance

Carole