5. Inventory

The components of inventory, net of allowance for obsolete, unmarketable or slow-moving inventories, are summarized as follows:


(in millions)	As of October 31, 2015		As of July 31, 2015
Raw materials	$	70.3	$	64.5
Work in process		42.6		46.0
Finished goods		31.8		22.2

Total inventory	$	144.6	$	132.7

A portion of our finished goods inventory is held by sales representatives, and is used in the field for both demonstration purposes and for sales to customers. During the quarter ended October 31, 2015, we modified our methodology for the valuation of demonstration inventory due to changes in how this inventory is being utilized. Previously, we provided a reserve for demonstration inventory over a four year period, until the point the inventory was either sold or disposed of. Beginning in the quarter ended October 31, 2015 and prospectively, demonstration inventory is valued by assessing its recoverability based on the age of the inventory and lower of cost or market considerations. A lower of cost or market reserve is recorded on demonstration inventory if based upon its age or our historical sales practices the utility of the inventory has declined below its carrying value. Once lower of cost or market reserves are recorded, they are not subsequently reversed, unless the inventory is sold or disposed of. We have applied this change in estimate prospectively, and the change in estimate did not result in a material impact to the historical or current period financial statements.