1. Clarify basic requirements: tonnage, space, and power 
    Tonnage and operating range 
        Light-duty (3-5 tons): suitable for indoor equipment installation, small steel structure lifting (such as glass curtain walls, roof materials), with a boom length of 8.3-10.5 meters, a working radius of 5-8.45 meters, a self-weight of about 2-2.7 tons, and can enter and exit elevators. 
        Medium-sized (8-12 tons): Used for subway construction and lifting of bridge prefabricated parts, with a boom length of up to 23.3 meters, a working radius of 22.7 meters, and stronger carrying capacity but larger size. 
        Key parameter matching: 
            Operating height: 9.2-9.5 meters (ground lift); 
            Underground operation: Some models support underground depths ranging from 10 to 40 meters (note that the lifting capacity may be affected by the wire rope's magnification ratio). 
    Spatial adaptability 
        Models with a width of ≤0.9 meters and a height of ≤1.6 meters can pass through doorways, stairs, and indoor corridors; 
        The track ground pressure is ≤42kPa (such as SPT299) or 36kPa (Yixun 3-ton), suitable for muddy ground and slopes (climbing ability 20°-30%). 
    Power selection 
        Dual-power system: diesel engine (outdoor 7.5-10.3KW) + electric motor (indoor 3-4KW AC380V), balancing environmental protection and power output; 
        The pure electric model is suitable for warehouses and shopping malls that do not require exhaust gas emissions. 
II. Core Configuration: Structure, Control, and Scalability 
    Jib and slewing system 
        Crane jib structure: Preferably choose a 5-6 section fully automatic telescopic jib (U-shaped or hexagonal design) to enhance rigidity and operational flexibility; 
        360° continuous rotation: Utilizing a worm gear or planetary reduction mechanism to ensure smooth rotation (rotation time 40-60 seconds per revolution). 
    Control method 
        Dual-mode operation: wireless remote control (range 100 meters) + manual control, ensuring safer switching in complex scenarios; 
        Proportional control system: enabling fine lifting operations (such as SPT299). 
    Expansion accessories 
        Common options: cradle (0.6-0.7t), jib, climbing frame, and support blocks; 
        Special requirements: Single/double rope winch (affecting the depth of underground operations). 
III. Safety performance: key protection and certification 
    Multiple safety devices 
        Torque limiter + overwind alarm + three-turn stop device to prevent overload; 
        "Leg off ground alarm + automatic shutdown when vehicle body tilt ≥ 3°;"; 
        The three modes of walking, outrigger, and boom are interlocked to prevent misoperation. 
    Stability design 
        The hydraulic outrigger has a maximum span of 4.7 meters (length) × 4.57 meters (width), featuring a frog-style structure with manual/automatic adjustment; 
        The level meter monitors the ground flatness in real time. 
    Certification standards 
        Mandatory certification: CE, ISO (essential for export), National III/EPA Tier 2 emissions (diesel engine models); 
        Warranty period: mainstream brands provide 1-2 years of warranty