The products are mainly used in building water supply and drainage, heating, ventilation, air conditioning, gas, heat, electricity, communication and fire and other mechanical and electrical installation works.1. Equipment with gravity greater than 1.8kN in suspension pipeline;2. Domestic water supply and drainage and fire control pipe system above DN65;3. The rectangular cross-sectional area is greater than or equal to 0.38 square meters and the circular diameter is greater than or equal to 0.7 meters;4. Cable tray and busway with inner diameter greater than 60mm electrical distribution pipe and gravity greater than or equal to 150 n/m.