Castle International Corp. (CCIC) is a real estate investment trust (REIT) company. The Company owns, operates and leases shared wireless infrastructure, including towers and other structures, such as rooftops (towers), and to a lesser extent, distributed antenna systems (DAS), a type of small cell network (small cells), and interests in land under third party towers in various forms (third party land interests). Its core business is renting space or physical capacity (collectively, space) on its towers, DAS and, to a lesser extent, third party land interests (collectively, site rental business) through long-term contracts in various forms, including license, sublease and lease agreements (collectively, contracts). The Company owned, leased or managed approximately 39,600 towers in the United States, including Puerto Rico, and approximately 1,700 towers in Australia.