# usage-product-inventories A Usage Product Inventory (UPI) is the assignment of a usage product to a Site. A UPI has 1 or more product reference (UPR) ## Get a list of available usage product inventories - [GET /usage-product-inventories](https://docs.elevatebilling.com/openapi/prod/gen/billing-rest-inventory/usage-product-inventories/getusageproductinventories.md) ## Check if usage product inventory exists - [HEAD /usage-product-inventories](https://docs.elevatebilling.com/openapi/prod/gen/billing-rest-inventory/usage-product-inventories/checkusageproductinventory.md) ## Create a new usage product inventory - [POST /usage-product-inventories](https://docs.elevatebilling.com/openapi/prod/gen/billing-rest-inventory/usage-product-inventories/createusageproductinventory.md) ## Get a specific usage product inventory - [GET /usage-product-inventories/{usage_product_inventory_id}](https://docs.elevatebilling.com/openapi/prod/gen/billing-rest-inventory/usage-product-inventories/getusageproductinventory.md) ## Update a usage product inventory - [PATCH /usage-product-inventories/{usage_product_inventory_id}](https://docs.elevatebilling.com/openapi/prod/gen/billing-rest-inventory/usage-product-inventories/updateusageproductinventory.md) ## Delete usage product inventory - [DELETE /usage-product-inventories/{usage_product_inventory_id}](https://docs.elevatebilling.com/openapi/prod/gen/billing-rest-inventory/usage-product-inventories/deleteusageproductinventory.md) ## Update a UPI product reference - [PATCH /usage-product-references/{product_reference_id}](https://docs.elevatebilling.com/openapi/prod/gen/billing-rest-inventory/usage-product-inventories/updateusageproductreference.md) ## Delete UPI product reference - [DELETE /usage-product-references/{product_reference_id}](https://docs.elevatebilling.com/openapi/prod/gen/billing-rest-inventory/usage-product-inventories/deleteusageproductreference.md)