If you know how to test it let me know please. Bought at estate sale. Dont know if it works. There is 2posts for 2 wires one must be ground the other power. Not sure what wire to attach to witch post to test. Or if you need a relay or not. There are no broken wires and only one very very minor dent on edge of horn as shown with my finger. Some light surface rust. The bolts are missing that hold the cover on easy to get from hardware store. If I can figure out how to test I will. It looks to me that it was never wired if you look at the case knock out spots were the cord is suppose go threw. Federal signal Horn IC/H2S4 US Navy. The item “Military federal signal Horn IC/H2S4 US Navy Ship” is in sale since Sunday, January 24, 2021. This item is in the category “Collectibles\Transportation\Boats & Ships\Military\Other Naval Collectibles”. The seller is “camaroguyred” and is located in Ashby, Massachusetts. This item can be shipped to United States, Canada, United Kingdom, Denmark, Romania, Slovakia, Bulgaria, Czech republic, Finland, Hungary, Latvia, Lithuania, Malta, Estonia, Australia, Greece, Portugal, Cyprus, Slovenia, Japan, China, Sweden, South Korea, Indonesia, Taiwan, South africa, Thailand, Belgium, France, Hong Kong, Ireland, Netherlands, Poland, Spain, Italy, Germany, Austria, Bahamas, Israel, Mexico, New Zealand, Philippines, Singapore, Switzerland, Norway, Saudi arabia, Ukraine, United arab emirates, Qatar, Kuwait, Bahrain, Croatia, Malaysia, Chile, Colombia, Costa rica, Panama, Trinidad and tobago, Guatemala, Honduras, Jamaica, Antigua and barbuda, Aruba, Belize, Dominica, Grenada, Saint kitts and nevis, Saint lucia, Montserrat, 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.