The 50th anniversary of the US Open will be highlighted by the unveiling of the 14,000-seat Louis Armstrong Stadium, but there are new accessories to admire as well.

Look out for the new clocks and oncourt furniture debuting in Flushing when the Open commences in 10 days.

According to the USTA, a “transparent’’ effort has been made to speed the pace and be consistent in eliminating unnecessary lag time. A clocking system will be in place for the first time at the Open to strictly enforce the rules.

A 25-second service clock will be omnipresent — visible at the southeast and northeast corners of the four showcourts and 13 field courts.

The Open will be the first Grand Slam event to decorate the grounds with service clocks. Previously, the chair umpires kept an informal clock in their heads to track whether a player deserved a delay of game warning.

The new format calls for the 25-second clock to wind down once a new score is announced by the chair. Failure to be in service motion by the time the clock expires will result in a newly conceived $1,000 fine, according to a source. Attempts by a player to excessively stall out of exhaustion — or an angry one lambasting an umpire — are likely over.

“The big reason we’re doing this is to be transparent with the players and the live and broadcast audience between points,’’ US Open tournament director David Brewer told The Post. “We want to get the information of the rules out there. There’s always a question about the pace of play. We’re encouraging the rules and time between points in a transparent way. It’s in the rules — loosely. It should resonate with New York fans.’’

The clock system will also be used in the lead-up before a new match in what the USTA calls the “1-5-1 warmup.’’

Brewer believes the warm-up time has been “fairly subjective.’’ Once the second player arrives on court, the two players have one minute to come to the net for the coin flip and hear instructions. The ensuing warm-up will be clocked at exactly five minutes. Thereafter, the players have just one minute after warm-up to start the match’s first point, giving them less motivation to fussing with their wrist and headbands. Violators will be fined.

“We think it’s good for everybody to be more precise,’’ Brewer said.

The clocking system was tested last year in the qualifiers and junior Open event and was trotted out on a trial run during this month’s US Open series tune-ups in Toronto, Montreal, Washington and Cincinnati.

“We didn’t want the Open to be the very first time the men and women are seeing it,’’ Brewer said.

At least the chair umpires will be more comfortable as they work the new clocks. For the first time since 1997 when Ashe Stadium debuted, all the oncourt furniture has been redesigned to make them more ergodynamic and lend a new look on the Open’s 50th anniversary. The Open was called the US National Championships during the amateur days pre-1968.

The architecture firm, Michael Graves, was hired to change the court furniture, including the umpire tower, the players chairs and the seats in which the linesmen crouch around the court. Also revamped were the cooler areas where players get drinks from coolers and find ball and towel bags.

“That area was a mess,’’ architect designer Donald Strum told The Post.

The two Graves designers, Strum and Rob Van Varick, talk about their furniture redo as if discussing pieces of fine art. Strum said one key challenge was making sure fan sight lines weren’t disrupted.

“It’s the Grand Slam in New York and we tried to develop the language that represented that,’’ Strum said.

Strum and Van Varick said the player chairs came with a vision of the park benches of Central Park and the umpire tower emulates the cantilevers of Manhattan “skyscrapers.”

The Graves architects believe the “flowing framework’’ of the new furniture is “very clean and fluid.’’ The tennis is expected to be the same.

The first match on the new Armstrong court will occur Wednesday before the Open. After a court dedication ceremony, John and Patrick McEnroe will face Michael Chang and James Blake.