A.5-10mm B.10-15mm C.10-20mm D.10-30mm
A.0.2-0.5m B.0.5-0.8m C.0.5-1.0m D.0.8-1.0m
A.風(fēng)管管徑 B.水管管井 C.電氣管井 D.強(qiáng)電管井