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Property, Plant and Equipment
6 Months Ended
Dec. 31, 2018
Property, Plant and Equipment [Abstract]  
Property, Plant and Equipment

5. Property, Plant and Equipment

  

Depreciation and amortization of property, plant and equipment was $698,000 and $615,000 for the six months ended December 31, 2018 and 2017, respectively. Inventory items included in property, plant and equipment are depreciated using the straight line method over estimated useful lives of 3 to 5 years. Depreciation of generators which are consigned to customers is expensed over a 5-year period, and depreciation is charged to selling expenses.