Inventories consist of the following (in thousands):

	December 31,
	2016				2015
Raw materials	$	54,359			$	51,439
Work in process	68,718				83,324
Finished goods	26,507				43,077
Inventories	$	149,584			$	177,840

We regularly review inventory quantities on hand and record a provision to write-down excess and obsolete inventory to its estimated net realizable value, if less than cost, based primarily on our estimated forecast of product demand. Once our inventory value is written-down a new cost basis has been established. For 2016, 2015 and 2014 our charges for slow moving, excess and obsolete inventory totaled $9.3 million, $15.4 million and $13.0 million respectively.

Our provision for inventory obsolescence allowances was $4.1 million, $5.2 million, and $5.0 million for the years ended of 2016, 2015 and 2014, respectively. As of December 31, 2016 we have $0.2 million of remaining structural landing gear inventory which we believe is recoverable based upon our net realizable value analysis that considers inventory demand, expected selling price, costs to transact, and costs to complete the inventory. We believe our inventory allowances remain adequate with the net realizable value of our inventory being higher than our current inventory cost after allowances.