16. SEGMENT INFORMATION

The Company has two operating segments, which are also its reportable segments. The Company's operating segments are organized based upon primary market channels and, in most instances, the end use of products.

Through its Electrical Raceway segment, the Company manufactures products that deploy, isolate and protect a structure's electrical circuitry from the original power source to the final outlet. These products, which include electrical conduit, armored cable, cable trays, mounting systems and fittings, are critical components of the electrical infrastructure for new construction and maintenance, repair and remodel markets. The vast majority of the Company's Electrical Raceway Net sales are made to electrical distributors, who then serve electrical contractors, and the Company considers both to be customers.

Through the MP&S segment, the Company provides products and services that frame, support and secure component parts in a broad range of structures, equipment and systems in electrical, industrial and construction applications. The Company's principal products in this segment are metal framing products and in-line galvanized mechanical tube. Through its metal framing business, the Company designs, manufactures and installs metal strut and fittings used to assemble mounting structures that support heavy equipment and electrical content in buildings and other structures.

Both segments use Adjusted EBITDA as the primary measure of profit and loss. Segment Adjusted EBITDA is the sum of income before income taxes, adjusted to exclude unallocated expenses, depreciation and amortization, interest expense, net, loss (gain) on extinguishment of debt, restructuring and impairments, stock-based compensation, consulting fees, multi-employer pension withdrawal, certain legal matters, transaction costs, gain on sale of joint venture and other items, such as inventory reserves and adjustments and realized or unrealized gain (loss) on foreign currency transactions.

Intersegment transactions primarily consist of product sales at designated transfer prices on an arms-length basis. Gross profit earned and reported within the segment is eliminated in the Company's consolidated results. Certain manufacturing and distribution expenses are allocated between the segments due to the shared nature of activities. Recorded amounts represent a proportional amount of the quantity of product produced for each segment.



	Three months ended
	December 29, 2017							December 30, 2016
(in thousands)	External Net Sales		Intersegment Sales			Adjusted EBITDA		External Net Sales		Intersegment Sales			Adjusted EBITDA
Electrical Raceway	$	316,005	$	518		$	56,160	$	241,939	$	446		$	42,117
MP&S	98,553		21			$	10,809	95,652		29			$	15,781
Eliminations	—		(539		)			—		(475		)
Consolidated operations	$	414,558	$	—				$	337,591	$	—

Presented below is a reconciliation of operating segment Adjusted EBITDA to Income before income taxes:



	Three months ended
(in thousands)	December 29, 2017			December 30, 2016
Operating segment Adjusted EBITDA
Electrical Raceway	$	56,160		$	42,117
MP&S	10,809			15,781
Total	66,969			57,898
Unallocated expenses ^(a)	(8,482		)	(8,007		)
Interest expense, net	(6,594		)	(9,830		)
Depreciation and amortization	(17,210		)	(13,628		)
Loss on extinguishment of debt	—			(9,805		)
Restructuring and impairments	(262		)	(389		)
Stock-based compensation	(3,564		)	(2,720		)
Transaction costs	(645		)	(1,560		)
Other	(507		)	10,930
Income before income taxes	$	29,705		$	22,889

(a) Represents unallocated selling, general and administrative activities and associated expenses including, in part, executive, legal, finance, human resources, information technology, business development and communications, as well as certain costs and earnings of employee-related benefits plans, such as stock-based compensation and a portion of self-insured medical costs.