"I still remember how everybody liked to fly kites in our primary school years," says Jimmy, now 32 years old.
"Now, most children don't do that. They only like to play video games," echoes brother Haiven, who is now 38 and a father of two. "My son [seven] isn't interested in kite-flying. He doesn't think it's exciting."
The two brothers have hung on to their childhood hobby. They fly kites with family or friends during the weekend. Their favourite spot is the Clear Water Bay Country Park.
"It's a very good way to de-stress," says Haiven. "We sit in an office all day. But when you fly a kite, you see the blue sky and white clouds and it's nice."
Says Jimmy: "It's comfortable to feel the wind and chat with your family at the same time. And you'd be surprised to see how many kite-flyers there are in Hong Kong. There are families, lovers and groups of friends."
Jimmy's wife, Carrie Ng Mei-ling, also shares the hobby with him. "It's a healthy hobby," she says. "You get to stay outdoors and enjoy the scenery. I think Hong Kong children need this kind of outdoor activity more."
Their shared passion has led them to start an online business called "kitehk.com" - it's a website selling kites and equipment such as hand wheels.
They launched the website in May. Business was slow in the first few months with only a few buyers as they had little time to market it while holding down full-time jobs.
But now they are attracting up to 40 buyers on average per month.
"Many [customers] tell us they like our kites, which are bigger and stronger. We sell modern kites that are made of better material, such as glass fibre or silk," says Haiven.
"Our hand wheels are also different and designed to control the rolling speed of the threads much easier and quicker." Haiven sources his gigantic kites from Weifang in Shandong province . Known as "the kingdom of kites", Weifang is home to the biggest annual international kite festival held on the mainland.
One of the signature products on their website is the "Octopus", a giant kite of 600cm in length and with no frames - a new design in the market. It also comes in a big red heart shape and a bright yellow happy face.
"We're the first to introduce the no-frame kites here in Hong Kong," Haiven says. "The special design with the little pockets on the kite makes it easy to fly."
The family wants to run their own business eventually, and not just selling kites. "Kites are only our beginning product," says Jimmy. "We plan to extend the business to other products as well." But the brothers say making money is not their ultimate goal. "We do this because we have lots of happy memories from flying kites. It's a happy event which connects the family," says Jimmy.