Inventories

Inventories on the Consolidated Balance Sheets are summarized as follows:



	March 29,		December 31,
(Thousands)	2019		2018
Raw materials and supplies	$	38,002	$	33,182
Work in process	194,548		195,879
Finished goods	36,838		30,643
Subtotal	$	269,388	$	259,704
Less: LIFO reserve balance	45,190		44,833
Inventories	$	224,198	$	214,871

The Company maintains the majority of the precious metals and copper used in production on a consignment basis in order to reduce our exposure to metal price movements and to reduce our working capital investment. The notional value of off-balance sheet precious metals and copper was $276.3 million as of March 29, 2019 versus $316.1 million as of December 31, 2018.