8.	Guarantees and Other Obligations

Product Warranty

Our products are generally sold with warranty periods that range from 12 to 36 months following sale or acceptance. Parts and labor are covered under the terms of the warranty agreement. The warranty provision is based on historical and projected experience by product and configuration.

Changes in accrued warranty were as follows

(

in thousands

)

	Three Months Ended						Nine Months Ended
	September 24,			September 26,			September 24,			September 26,
	2016			2015			2016			2015
Balance at beginning of period	$	5,118		$	5,212		$	4,886		$	5,848
Warranty expense accruals		1,320			1,867			4,586			5,062
Warranty payments		(1,401	)		(1,905	)		(4,435	)		(5,736	)
Balance at end of period	$	5,037		$	5,174		$	5,037		$	5,174

Accrued warranty amounts expected to be incurred after one year are included in noncurrent other accrued liabilities in the condensed consolidated balance sheet. These amounts total $1.3 million at September 24, 2016 and $1.1 million at December 26, 2015.

Standby Letters of Credit

During the ordinary course of business, we provide standby letters of credit instruments to certain parties as required. As of September 24, 2016, no amounts were outstanding under standby lines of credit.

Lines of Credit

One of our wholly owned subsidiaries has two available lines of credit which provide it with borrowings of up to a total of 2.5 million Swiss Francs. At September 24, 2016 and December 26, 2015, no amounts were outstanding under the lines of credit.