They were only installed and used for testing a particular need for a project. We removed them and they do not show any signs of use. See pictures for info on adjustability of voltage and amperage. The item "Adjustable DC Power Supply. AC 110V to DC 0-48V 0-21A" is in sale since Thursday, June 20, 2019.This item is in the category "Business & Industrial\Test, Measurement & Inspection\Signal Sources & Conditioning\Adjustable Power Supplies". The seller is "thekittytube" and is located in Hudson, Wisconsin. This item can be shipped to United States, Canada, United Kingdom, China, Mexico, Germany, Japan, France, Australia, Denmark, Romania, Slovakia, Bulgaria, Czech republic, Finland, Hungary, Latvia, Lithuania, Malta, Estonia, Greece, Portugal, Cyprus, Slovenia, Sweden, South Korea, Indonesia, Taiwan, South africa, Thailand, Belgium, Hong Kong, Ireland, Netherlands, Poland, Spain, Italy, Austria, Bahamas, Israel, New Zealand, Philippines, Singapore, Switzerland, Norway, Saudi arabia, United arab emirates, Qatar, Kuwait, Bahrain, Croatia, Malaysia, Chile, Colombia, Costa rica, Dominican republic, Panama, Trinidad and tobago, Guatemala, El salvador, Honduras, Jamaica, Antigua and barbuda, Aruba, Belize, Dominica, Grenada, Saint kitts and nevis, Saint lucia, Turks and caicos islands, Barbados, Bangladesh, Bermuda, Brunei darussalam, Bolivia, Egypt, French guiana, Guernsey, Gibraltar, Guadeloupe, Iceland, Jersey, Jordan, Cambodia, Cayman islands, Liechtenstein, Sri lanka, Luxembourg, Monaco, Macao, Martinique, Maldives, Nicaragua, Oman, Pakistan, Paraguay, Reunion, Uruguay.