Fifteen units had been sold and five remained on the market as of mid-April at Brownstone Realtors Partners Development Corporation's building. There were three two-bedroom units and two three-bedroom duplex penthouse units available. The units range from 900 to 1,463 square feet and are priced from $499,000 to $795,000. The building has storage, a landscaped public and private terraces and a 25-year 421-a tax abatement. Contact A.N. Shell Realty Group.