The two fifth formers from Yan Chai Hospital No 2 Secondary School are both top players of the Hong Kong junior volleyball team. Often it can be hard to tell them apart on the court- or off it.
Wing-tung was born seven minutes earlier than Wing-man. That little time difference in age set a pecking order between them. They often bickered and fought as children, they admit.
Gone now are those days of discord. Playing volleyball on the same team has given the twins a unity of purpose.
"We go to the same place for the same purpose many times every week," Wing-man explains. "If I play badly on the court, sometimes I can't hold my tears back on the sidelines," she adds.
Her tears do not leave Wing-tung unaffected. "Whenever she cries on the court, I don't know why, but I feel like crying too," Wing-tung says.
The two girls do seem inseparable.
Take an incident at the final of the Jing Ying Tournament last New Year's Eve. Wing-man's arm was injured when she crashed into another teammate while trying to retrieve the ball.
As she winced in pain, Wing-tung ran up to comfort her. Her sister's pep-talk let her forget about her pain. She threw herself back into the game and the twins helped their team win the match.
The twins are both in top form. They have helped their school team win inter-school titles, the Jing Ying Tournament and the inter-school beach volleyball competition.
Their road to glory began at a leadership training camp two years ago. There they met the teacher in charge of the volleyball team of TWGHs Kwok Yat Wai College, where they were studying at the time. He was impressed by the twin's performance both on the basketball and volleyball courts. He hand-picked them for volleyball training.
The To sisters' success in the sport in such a short time was helped by their 1.75m height.
"We have grown taller and stronger together on the volleyball court in Tin Sau Road Park," Wing-tung says.
"We are no longer afraid of heavy spikes from opponents. We can even stand up to boys' teams on the court."
Playing volleyball has also brought the sisters together in their personal relationship.
Next up on their joint schedule is the interport competition in Macau later this month. Then they will be off to represent Hong Kong at the All China Secondary School Students Games to be held in Inner Mongolia in July.
Stay tuned for updates about the twins' doings in Young Post and on yp.scmp.com