Property, plant, and equipment consists of the following:


	December 31, 2020		September 30, 2020
Machinery and equipment	$	363,338	$	357,650
Rental equipment	230,027		221,953
Land and buildings	70,709		70,245
Construction in process	51,923		48,325
	715,997		698,173
Less: accumulated depreciation	(346,082)		(333,712)
	$	369,915	$	364,461

The Company entered into secured financing agreements that require providing a security interest in specified equipment. As of December 31, 2020 and September 30, 2020, the gross and net amounts of those assets are as follows:


	December 31, 2020				September 30, 2020
	Gross		Net		Gross		Net
Machinery and equipment	$	65,285	$	53,214	$	63,305	$	52,620
Construction in process	13,978		13,978		8,098		8,098
	$	79,263	$	67,192	$	71,403	$	60,718

Depreciation expense and maintenance and repairs expense for the three months ended December 31, 2020 and 2019 were as follows:


	Three Months Ended December 31,
		2020		2019
Depreciation expense		$	18,511	$	17,303
Maintenance and repair expense		5,208		6,065