An anonymous Brooklyn-based LLC has filed applications for a four-story, eight-unit residential building at 545 St. Marks Avenue, in western Crown Heights. The project will measure 7,324 square feet and its residential units should average 813 square feet apiece, indicative of rental apartments. There will be two apartments per floor, although one of the fourth-floor units will also feature upper penthouse space. Issac & Stern Architects is the architect of record. The 2,184-square-foot site is vacant.