I plan to stay in Shenzhen and for a few days will travel to and from hong kong.

1. You can take subway to Luohu Station, then go through customs to HK.
2. Children with 1.2-1.5 metre-tall should purchase children's tickets, which is calculated at 50% of the ticket price. Each adult passenger can only bring a child less than 1.2 metres tall without occuping a single seat, the exceeded child should purchase ticket.