Inventories are valued using the last-in, first-out (LIFO) method. An actual valuation of inventory under the LIFO method can be made only at the end of each year based on the inventory levels and costs existing at that time. Accordingly, interim LIFO calculations must necessarily be based on management's estimates of expected year-end inventory levels and costs. Because these are subject to many factors beyond management's control, interim results are subject to the final year-end LIFO inventory valuation.

During the nine month period ended September 26, 2020, inventory quantities were reduced. If this reduction remains through year-end, it will result in a liquidation of LIFO inventory quantities carried at lower costs prevailing in prior years as compared with the current cost of purchases. Although the effect of such a liquidation cannot be precisely quantified at the present time, management believes that if a LIFO liquidation occurs in 2020, the impact may be material to the Company’s results of operations for the period but will not have a material impact on the financial position of the Company.

Inventories consist of the following:

	September 26, 2020	December 31, 2019
Inventory at FIFO
Finished products	$3,734	$13,131
Materials and work in process	60,192	65,880
Gross inventories	63,926	79,011
Less: LIFO reserve	(47,331)	(47,137)
Less: excess and obsolescence reserve	(3,016)	(3,573)
Net inventories	$13,579	$28,301