In the atrium at 701 B St., one hears piano music several times a day. But don’t look for the pianist. The instrument, thought to be more than a century old, has been converted to a player piano that automatically bursts into music daily from 7-9 a.m., 11 a.m.-1 p.m. and 4-6 p.m.

This 544,000-square-foot Class A building, owned by Arden Realty Limited Partnership and opened in 1982, is one of the largest in the county. It also is one of the top in energy efficiency, having received the U.S. government’s Energy Star Award for the past four years.

Called the Darth Vader Building in the past because of its black exterior and rounded corners, it is actually the Merrill Lynch building. The brokerage firm occupies the top two floors of the 24-story structure, but it is not the largest space used by one company. That honor goes to the Latham & Watkins law firm, a tenant since the building opened. Ironically, the law firm is moving to One America Plaza where it will fill four floors. Its former space already has been spoken for by Arrowhead General Insurance.

Building Manager Don Petros chuckles slightly at the Darth Vader reference, and says, “That’s an unfriendly image we’d like to change. It’s really a very friendly building once you come inside.”

The tenant makeup of the building is diverse. It includes the San Diego Athletic Club, the oldest Downtown gym with a squash court and aerobic room; third floor conference rooms that tenants may use at no charge; the 80-foot high atrium, which is available for tenant use and can be rented to the public; and the popular Scott’s Gourmet Sandwiches.

Work Space details:

Building Name: 701 B St. and the Merrill Lynch Building

Address: 701 B St., San Diego

Owner: Arden Realty Limited Partnership

Date Opened: 1982

Number of Floors: 24

Gross Square Footage: 544,000 square feet

Space Available: 58,901 square feet

Key Space Available: Entire 14th Floor: 22,486 rentable square feet.

Lease Rate Range: $2.20-$2.40 per square foot per month, full service.

Number of Tenants: 39

Key Tenants: Merrill Lynch, Prudential Securities, Deloitte & Touche, Equitable Life.

Parking Spaces: 479

Special Amenities: San Diego Athletic Club, Scott’s Gourmet Sandwiches, conference center.

Fun Facts: 80-foot-high atrium lobby, with a piano more than 100 years old.

Building Manager: Don Petros

Manager Contact Info: (619) 230-1900

Broker: Colliers International

Broker Contact Info: Tim Cowden, (619) 595-0824, John Shelton, (619) 595-0823.