6. Inventory

Non-core inventory, inventory unreturned, long-term core inventory, and long-term core inventory deposits are as follows at March 31:

	2017			2016
Non-core inventory
Raw materials	$	21,515,000		$	17,394,000
Work in process		641,000			135,000
Finished goods		48,337,000			42,982,000
		70,493,000			60,511,000
Less allowance for excess and obsolete inventory		(2,977,000	)		(2,451,000	)
Total	$	67,516,000		$	58,060,000

Inventory unreturned	$	7,581,000		$	10,520,000
Long-term core inventory
Used cores held at the Company's facilities	$	38,713,000		$	34,405,000
Used cores expected to be returned by customers		11,752,000			10,781,000
Remanufactured cores held in finished goods		27,667,000			24,489,000
Remanufactured cores held at customers' locations (1)		185,938,000			172,600,000
		264,070,000			242,275,000
Less allowance for excess and obsolete inventory		(1,148,000	)		(1,175,000	)
Total	$	262,922,000		$	241,100,000

Long-term core inventory deposits	$	5,569,000		$	5,569,000

(1)	Remanufactured cores held at customers’ locations represent the core portion of the Company’s customers’ finished goods at the Company’s customers’ locations.