CHICAGO — Clear Height Properties has acquired a four-property, 522,000-square-foot industrial and office portfolio in suburban Chicago for $30 million. The portfolio includes a 201,800-square-foot office building in Oak Brook as well as more than 320,000 square feet of flex properties in Elmhurst, Bensenville and Willowbrook. The office building was 81 percent leased at the time of acquisition. Clear Height plans to upgrade the amenities, including the fitness center, lobby and conference facilities. The other properties include Elmhurst Metro Court in Elmhurst, Tower Lane Business Park in Bensenville and Willowbrook Court in Willowbrook. Transwestern represented the seller, a private investor.