供水管及排水管鋪設
Classification Hierarchy
Air-conditioning and ventilation system, installation and maintenance
空氣調節及通風系統安裝及保養
Water well drilling
鑽水井
Gas fitting, installation and maintenance
燃氣供應系統裝設、安裝及保養
Combined and other ventilation, gas and water fitting, installation and maintenance
綜合及其他通風、燃氣及水務設備安裝及保養