The Company leases a piece of land and some buildings in Singapore under non-cancellable operating lease arrangements for terms from 1 to 30 years.

Future minimum rental payable under non-cancellable operating leases with initial terms of one year or more consisted of the following:

	As of December 31,
	2018		2017
	US$’000		US$’000
Within one year		616		1,174
After one year but not more than five years		1,279		859
More than five years		1,368		1,607
		3,263		3,640

Future minimum payments under finance leases with initial terms of one year or more consisted of the following as of December 31:

	2018					2017
	Minimum payments			Present value of payments		Minimum payments			Present value of payments
	US$’000			US$’000		US$’000			US$’000
Within one year		47			44		39			36
After one year but not more than five years		47			46		44			42
More than five years		—			—		—			—
Total minimum lease payments		94			90		83			78
Less: amount representing finance charges		(4	)		—		(5	)		—
Present value of minimum lease payment		90			90		78			78

The finance lease liabilities are secured by the leased motor vehicles. The average discount interest rate implicit in the lease is 5.18% and 5.11%, for 2018 and 2017, respectively.

As of December 31, 2018 and 2017, the Company and its subsidiaries had commitments to purchase raw materials totaling $136 million to $176 million and $175 million to $277 million (22,450 to 28,940 metric tons and 24,005 to 37,930 metric tons), respectively, from third parties at the prices stipulated in the contracts.

As of December 31, 2018 and 2017, the Company and its subsidiaries had capital commitment relating to the construction of factory building improvement and acquisition of machinery, totaling $0.6 million and $0.8 million, respectively.

As of December 31, 2018 and 2017, one of Charoong Thai’s subsidiaries had guarantee obligations of bank credit line of its operating subsidiary at approximately $2 million and $2 million, respectively.

As of December 31, 2018 and 2017, the Company provided a corporate guarantee not exceeding the sum of $24.3 million and $31.2 million, respectively, for the bond performance and banking facility of Sigma Cable.

As of December 31, 2018 and 2017, there were outstanding bank guarantees of $36.9 million and $35.2 million, respectively, issued by the banks on behalf of Charoong Thai and its subsidiaries in respect of certain performance bonds as required in the normal course of business of the companies. These guarantees generally expire within 1 year.

As of December 31, 2018 and 2017, the Company and its subsidiaries had commitments in respect of repair and maintenance consulting services with related parties totaling $0.2 million and $0.1 million, respectively.