Commitments and Contingent Liabilities Guarantees: Standby letters of credit were issued to lessors and insurance institutions and can only be drawn upon in the event of our failure to pay our obligations to a beneficiary. As of December 31, 2018 , we had a maximum financial exposure from unused standby letters of credit totaling $1.4 million . We are not aware of circumstances that would require us to perform under these arrangements and believe that the resolution of any claims that might arise in the future, either individually or in the aggregate, would not materially affect our condensed consolidated financial statements. Accordingly, no liability has been recorded as of December 31, 2018 with respect to the standby letters of credit. We also enter into commercial letters of credit to facilitate payments to vendors and from customers. Product Warranties: We provide an assurance-type warranty that guarantees our product complies with agreed-upon specifications. This warranty is not sold separately and does not convey any additional services to the customer. We estimate product warranty liability at the time of sale based on historical repair or replacement cost trends in conjunction with the length of the warranty offered. Management refines the warranty liability periodically based on changes in historical cost trends and in certain cases where specific warranty issues become known. Changes in the product warranty accrual for the six months ended December 31, 2018 and 2017 were as follows: Six Months Ended December 31 (Amounts in Thousands) 2018 2017 Product Warranty Liability at the beginning of the period $ 2,294 $ 1,992 Additions to warranty accrual (including changes in estimates) 354 839 Settlements made (in cash or in kind) (606 ) (478 ) Product Warranty Liability at the end of the period $ 2,042 $ 2,353