Shalom Stahler, through Aron Engel LLC, purchased a two-unit office building at 104 Montgomery Street in Crown Heights, Brooklyn, for $9 million. The property, which has 12,393 square feet of built space and 25,082 square feet of additional air rights, allows for a total buildable area of 37,468 square feet. The sale price per built square foot was $726, and the price per buildable square foot was $240. The buyer plans for ground-up development. The property is zoned R8A, allowing residential development with inclusionary housing.